Group 18 elements are called noble gases and not inert gases because compounds of Kr, Xe and Rn have been prepared. Their general electronic configuration is \(ns^2\)\(np^6\) except He(\(1s^2\) ). They have highest ionisation enthalpy and positive electron gain enthalpy due to stable electronic configuration. Helium is found in sun and stars. Noble gases have low boiling points due to weak van der Waals’ forces of attraction. Xenon forms \(XeF_2\), \(XeF_4\), \(XeF_6\), \(XeOF_4\), \(XeO_3\), \(XeO_2\)\(F_2\), their structures can be drawn on bases of VSEPR theory. Helium is mixed with oxygen by deep sea divers to avoid pain. Neon is used in coloured advertising lights. Argon is used in bulbs as inert gas. Kr and Xe are used in high efficiency lamps, head light of cars. Radon is radioactive formed by a-decay of Radium 226 88Ra Argon is most abundant (0.9%) noble gas in atmosphere.
The following questions are multiple choice questions. Choose the most appropriate answer.
1) What are the elements in group 18 (the far right) of the periodic table called?
a) Alkali metals
b) Alkaline earth metals
c) Halogens
d) Noble gases
2) Out of (i) \(XeO_3\) (ii) \(XeOF_4\) and (iii) \(XeF_6\) , the molecules having the same number of lone pairs on Xe are -
a) (i) and (ii) only
b) (i) and (iii) only
c) (ii) and (iii) only
d) (i) , (ii) and (iii)
3) Which one has linear shape?
a) \(XeF_2\)
b) \(XeF_4\)
c) \(XeF_6\)
d) \(XeO_3\)
4) Which of the outer electronic configuration represent Argon?
a) \(ns^2\)\(np^4\)
b) \(ns^2\)\(np^3\)
c) \(ns^2\)\(np^6\)
d) \(ns^1\)\(np^6\)
5) Which of the following statement is false?
a) Radon is obtained from the decay of radium
b) Helium is an inert gas
c) Xenon is the most reactive among the rare gases
d) The most abundant rare gas found in the atmosphere is helium
The following questions are multiple choice questions. Choose the most appropriate answer.
1) What are the elements in group 18 (the far right) of the periodic table called?
a) Alkali metals
b) Alkaline earth metals
c) Halogens
d) Noble gases
2) Out of (i) \(XeO_3\) (ii) \(XeOF_4\) and (iii) \(XeF_6\) , the molecules having the same number of lone pairs on Xe are -
a) (i) and (ii) only
b) (i) and (iii) only
c) (ii) and (iii) only
d) (i) , (ii) and (iii)
3) Which one has linear shape?
a) \(XeF_2\)
b) \(XeF_4\)
c) \(XeF_6\)
d) \(XeO_3\)
4) Which of the outer electronic configuration represent Argon?
a) \(ns^2\)\(np^4\)
b) \(ns^2\)\(np^3\)
c) \(ns^2\)\(np^6\)
d) \(ns^1\)\(np^6\)
5) Which of the following statement is false?
a) Radon is obtained from the decay of radium
b) Helium is an inert gas
c) Xenon is the most reactive among the rare gases
d) The most abundant rare gas found in the atmosphere is helium
1) d) Noble gases
2) d) (i) , (ii) and (iii)
3) a) \(XeF_2\)
4) c) \(ns^2\)\(np^6\)
5) d) The most abundant rare gas found in the atmosphere is helium
2) d) (i) , (ii) and (iii)
3) a) \(XeF_2\)
4) c) \(ns^2\)\(np^6\)
5) d) The most abundant rare gas found in the atmosphere is helium
Group 16 elements are called chalcogens i.e., ore forming elements (oxygen, sulphur, selenium etc.) because most of the ores are oxides and sulphides. Oxygen is gas where as other elements of group 16 are solids. Oxygen shows anomalous behaviour. Oxygen is diatomic where is sulphur exists as \(S_8\) which has crown shaped structure. It shows allotropy. Sulphur is present in onion and garlic that is why they have pungent smell. Sulphur is used for manufacture of sulphuric acid which is called ‘King of chemicals’, used in fertilizer, detergents, dyes and drugs.
The following questions are multiple choice questions. Choose the most appropriate answer.
1) Group 16 elements are also known as
a) Noble elements
b) Halogens
c) Pnictogens
d) Chalcogens
2) Acidic character of hydrides of group 16 elements is in the order
a) \(H_2\)O < \(H_2\)S < \(H_2\)Se < \(H_2\)Te
b) \(H_2\)S < \(H_2\)Se < \(H_2\)Te < \(H_2\)O
c) \(H_2\)O < \(H_2\)Se < \(H_2\)Te < \(H_2\)S
d) \(H_2\)O < \(H_2\)S < \(H_2\)Te < \(H_2\)Se
3) Hybridisation of S in \(SF_4\) and geometry of \(SF_4\) are respectively
a) \(sp^3\)d, trigonal pyramidal
b) \(sp^3\)d, see saw
c) \(sp^3\), tetrahedral
d) \(dsp^2\), square planner
4) Which is not an acidic oxide?
a) \(CO_2\)
b) \(SO_2\)
c) \(Na_2\)O
d) \(Cl_2\)\(O_7\)
5) Which is not correct about allotropes of sulphur
a) The stable form at room temperature is rhombic sulphur
b) Monoclinic sulphur is stable above 369 K and transforms into rhombic sulphur below it
c) At 369 K both the forms are stable
d) Monoclinic sulphur is soluble in \(CS_2\) while rhombic sulphur not
Assertion :- Interhalogen compounds are more reactive than halogen.
Reason :- They all undergo hydrolysis giving halide, cation derived from the smaller halogen & anion derived from larger halogen.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Assertion:-The stability of hydrides decreases from \(NH_3\) to \(BiH_3\).
Reason:-There is a decrease in bond dissociation enthalpy of bond E-H from \(NH_3\) to \(BiH_3\). (E=Element of group 15)
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Assertion :-Solubility of noble gases in water decreases with increasing size of the noble gases.
Reason :- Solubility of noble gases in water is due to dipole- dipole interaction.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Assertion :- Nitrogen has higher ionisation enthalpy than that of oxygen.
Reason :- Nitrogen has smaller atomic size than that of Oxygen.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Assertion:-Nitrogen is restricted to a maximum covalency of 4.
Reason:-Nitrogen exists as a diatomic molecule (\(N_2\)) with a triple bond.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Assertion:- \(H_2\)O is the only hydrides of the Chalcogens which is liquid.
Reason :- In ice each O atom is surrounded by 4H-atom.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
Group 18 elements are called noble gases and not inert gases because compounds of Kr, Xe and Rn have been prepared. Their general electronic configuration is \(ns^2\)\(np^6\) except He(\(1s^2\) ). They have highest ionisation enthalpy and positive electron gain enthalpy due to stable electronic configuration. Helium is found in sun and stars. Noble gases have low boiling points due to weak van der Waals’ forces of attraction. Xenon forms \(XeF_2\), \(XeF_4\), \(XeF_6\), \(XeOF_4\), \(XeO_3\), \(XeO_2\)\(F_2\), their structures can be drawn on bases of VSEPR theory. Helium is mixed with oxygen by deep sea divers to avoid pain. Neon is used in coloured advertising lights. Argon is used in bulbs as inert gas. Kr and Xe are used in high efficiency lamps, head light of cars. Radon is radioactive formed by a-decay of Radium 226 88Ra Argon is most abundant (0.9%) noble gas in atmosphere.
The following questions are multiple choice questions. Choose the most appropriate answer.
1) What are the elements in group 18 (the far right) of the periodic table called?
a) Alkali metals
b) Alkaline earth metals
c) Halogens
d) Noble gases
2) Out of (i) \(XeO_3\) (ii) \(XeOF_4\) and (iii) \(XeF_6\) , the molecules having the same number of lone pairs on Xe are -
a) (i) and (ii) only
b) (i) and (iii) only
c) (ii) and (iii) only
d) (i) , (ii) and (iii)
3) Which one has linear shape?
a) \(XeF_2\)
b) \(XeF_4\)
c) \(XeF_6\)
d) \(XeO_3\)
4) Which of the outer electronic configuration represent Argon?
a) \(ns^2\)\(np^4\)
b) \(ns^2\)\(np^3\)
c) \(ns^2\)\(np^6\)
d) \(ns^1\)\(np^6\)
5) Which of the following statement is false?
a) Radon is obtained from the decay of radium
b) Helium is an inert gas
c) Xenon is the most reactive among the rare gases
d) The most abundant rare gas found in the atmosphere is helium
Proteins are high molecular mass complex biomolecules of amino acid The important proteins required for our body are enzymes, hormones, antibodies, transport proteins, structural proteins, contractile proteins etc. Except for glycine, all o-amino acids have chiral carbon atom and most of them have L-configuration. The amino acids exists as dipolar ion called zwitter ion, in which a proton goes from the carboxyl group to the amino group. A large number of-amino acids are joined by peptide bonds forming polypeptides. The peptides having very large molecular mass (more than 10,000) are called proteins. The structure of proteins is described as primary structure giving sequence of linking of amino acids; secondary structure giving manner in which polypeptide chains are arranged and folded; tertiary structure giving folding, coiling or bonding polypeptide chains producing three dimensional structures and quaternary structure giving arrangement of sub- units in an aggregate protein molecule.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
c) Assertion is correct statement but reason is wrong statement.
d) Assertion is wrong statement but reason is correct statement.
i) Assertion .- All amino acids are optimally active.
Reason : Amino acids contain asymmetric carbon atoms.
ii) Assertion .- In o-helix structure, intramolecular H-bonding takes place whereas in β-pleated structure,intermolecular H-bonding takes place.
Reason : An egg contains a soluble globular protein called albumin which is present in the white part.
iii) Assertion .- Secondary structure of protein refers to regular folding patterns of continuous portions of the polypeptide chain
Reason : Out of 20 amino acids, only 12 amino acids can be synthesized by human body.
iv) Assertion .- The. helical structure of protein is stabilized by intramolecular hydrogen bond between —NH and carbonyl oxygen.
Reason : Sanger’s reagent is used for the identification of N-terminal amino acid of peptide chain.
The properties of the solutions which depend only on the number of solute particles but not on the nature of the solute are called colligative properties. Relative lowering in vapour pressure is also an example of colligative properties. For an experiment, sugar solution is prepared for which lowering in vapour pressure was found to be 0.061 mm of Hg.(vapour pressure of water at \(20^\circ\)C is 17.5 mm of Hg).
Answer the following MCQs by choosing the most appropriate options:
(i) Relative lowering of vapour pressure for the given solution is-
(a) 0.00348
(b) 0.061
(c) 0.122
(d) 1.75
(ii) The vapour pressure (mm of Hg) of Solution will be
(a) 17.5
(b) 0.61
(c) 17.439
(d) 0.00348
(iii) Mole fraction of sugar in the solution is
(a) 0.00348
(b) 0.9965
(c) 0.061
(d) 1.75
(iv) If weight of sugar taken is 5 g in 108 g of water then molar mass of sugar will be
(a) 358
(b) 120
(c) 240
(d) 400
(v) The vapour pressure (mm of Hg) of water at 293 K when 25 g of glucose is dissolved in 450 g of water is
(a) 17.2
(b) 17.4
(c) 17.120
(d) 17.02
Read the passage given below and answer the following questions:
In an ideal crystal, there must be regular repeating arrangement of the constituting particles and its entropy must be zero at absolute zero temperature. However, it is impossible to obtain an ideal crystal and it suffers from certain defects called imperfections. In pure crystal, these defects arises either due to disorder or dislocation of the constituting particles from the normal positions or due to the movement of the particles even at absolute zero temperature. Such defects increase with rise in temperature. In addition to these certain defects arise due to the presence of some impurities. Such defects not only modify the existing properties of the crystalline solids but also impart certain new characteristics to them.
Answer the following MCQs by choosing the most appropriate options:
1) AgCl is crystallized from molten AgCl containing a little \(CdCl_2\). The solid obtained will have
(a) cationic vacancies equal to number of \(Cd^{2+}\) ions incorporated.
(b) cationic vacancies equal to double the number of \(Cd^{2+}\) ions.
(c) anionic vacancies.
(d) neither cationic nor anionic vacancies.
2) Lattice defect per \(10^{15}\) NaCl is 1. What is the number of lattice defects in a mole of NaCl?
(a) 6.02 × \(10^{23}\)
(b) 6.02 × \(10^8\)
(c) \(10^{14}\)
(d) None of these
3) The ionic substances in which the cation and anion are of almost similar size shows
(a) non-stoichiometric defect
(b) Schottky defect
(c) Frenkel defect
(d) all of these
4) Which of the following gives both Frenkel and Schottky defect?
(a) AgCl
(b) CsCl
(c) KCl
(d) AgBr
Boiling point or freezing point of liquid solution would be affected by the dissolved solids in the liquid phase. A soluble solid in solution has the effect of raising its boiling point and depressing its freezing point. The addition of non-volatile substances to a solvent decreases the vapor pressure and the added solute particles affect the formation of pure solvent crystals. According to many researches the decrease in freezing point directly correlated to the concentration of solutes dissolved in the solvent. This phenomenon is expressed as freezing point depression and it is useful for several applications such as freeze concentration of liquid food and to find the molar mass of an unknown solute in the solution. Freeze concentration is a high quality liquid food concentration method where water is removed by forming ice crystals. This is done by cooling the liquid food below the freezing point of the solution. The freezing point depression is referred as a colligative property and it is proportional to the molar concentration of the solution (m), along with vapor pressure lowering, boiling point elevation, and osmotic pressure. These are physical characteristics of solutions that depend only on the identity of the solvent and the concentration of the solute. The characters are not depending on the solute’s identity.
Answer the following MCQs by choosing the most appropriate options:
(i) When a non volatile solid is added to pure water it will-
(a) boil above \(100^\circ\)C and freeze above \(0^\circ\)C.
(b) b) boil below \(100^\circ\)C and freeze above \(0^\circ\)C.
(c) boil above \(100^\circ\)C and freeze below \(0^\circ\)C.
(d) boil below \(100^\circ\)C and freeze below \(0^\circ\)C.
(ii) Colligative properties are
(a) dependent only on the concentration of the solute and independent of the solvent’s and solute’s
identity.
(b) dependent only on the identity of the solute and the concentration of the solute and independent
of the solvent’s identity.
(c) dependent on the identity of the solvent and solute and thus on the concentration of the solute.
(d) dependent only on the identity of the solvent and the concentration of the solute and independent
of the solute’s identity.
(iii) Assume three samples of juices A, B and C have glucose as the only sugar present in them. The concentration of sample A, B and C are 0.1 M, 0.5 M and 0.2 M respectively. Freezing point will be highest for the fruit juice
(a) A
(b) B
(c) C
(d) all have same freezing point
(iv) Identify which of the following is a colligative property?
(a) Freezing point
(b) Boiling point
(c) Osmotic pressure
(d) All of the above
An organic compound A having molecular formula \(C_6\)\(H_6\)O turn blue litmus solution into red but does not react with sodium bicarbonate, but when treated with bromine water then form a white ppt of compound B. when compound A react with chloroform in presence of aqueous caustic soda solution at 340K then form two compound C and D. When compound A treated with caustic soda then form compound E compound E when treated with methyl halide then form compound F.
Read the above passage carefully and answer the following questions:
(i) The name of compound is:
(a) 2-methyl propene-2-ol
(b) 2-methyl phenol
(c) 2,4,6-tribromophenol
(d) Butane 1-ol
(ii) Which are isomers of each other
(a) A and C
(b) B and C
(c) C and D
(d) D and E
(iii) The IUPAC name of compound F is
(a) Anisole
(b) Methoxybenzene
(c) Salicylaldehyde
(d) 2-methyl propene-2-ol
(iv) When compound E treated with ethyl iodide then ...... form.
(a) Ehoxybenzene
(b) Ethoxy hexane
(c) Propoxypropane
(d) Benzaldehyde
(v) On oxidation with sodium dichromate and conc \(H_2\)\(SO_4\) phenol gives
(a) Benzaldehyde
(b) p-Benzoquinone
(c) o-Benzoquinone
(d) m-benzoquinone
Read the passage given below and answer the following questions:
The replacement of hydrogen atom in a hydrocarbon, aliphatic or aromatic results in the formation of haloalkanes and haloarenes respectively. Haloalkanes contain halogen atom attached to \(sp^3\) hybridised carbon atom of an alkyl group whereas haloarenes contain halogen atom attached to \(sp^2\) hybridised carbon atom of an aryl group. Haloalkanes and haloarenes may be classified on the basis of number of halogen atoms in their structures as mono, di or poly halogen compounds and also on the basis of the state of hybridisation of carbon atom to which the halogen atom is bonded.
(i) Which of the following halide is 2°?
(a) Isopropyl chloride
(b) Isobutyl chloride
(c) n-propyl chloride
(d) n-butyl chloride
(ii) Which of the following is a Gem-dibromide is :
(a) \(CH_3\)\(CH(Br)CH_2\)(Br)
(b) \(CH_3\)\(CBr_2\)\(CH_3\)
(c) \(CH_2\)\((Br)CH_2\)\(CH_2\)
(d) \(CH_2\)\(BrCH_2\)Br
(iii) IUPAC name of (\({\\(CH_3\\)}_3\))CCl is:
(a) 3-Chlorobutane
(b) 2-Chloro-2-methylpropane
(c) t-butyl chloride
(d) n-butyl chloride
(iv) Which of the following is a primary halide?
(a) Isopropyl iodide
(b) Secondary butyl iodide
(c) Tertiarybutylbromide
(d) Neohexylchloride
(v) Which one of the following is not an allylic halide?
(a) 4-Bromopent-2-ene
(b) 3-Bromo-2-methylbut-1-ene
(c) 1-Bromobut-2-ene
(d) 4-Bromobut-1-ene