The ionisation enthalpy of the group 15 elements is much greater than that of group 14 elements in the corresponding periods. Which is the most suitable reason?
a) more effective nuclear charge
b) presence of stable half-filled electronic configuration
c) smaller size
d) high electronegativity
a) more effective nuclear charge
b) presence of stable half-filled electronic configuration
c) smaller size
d) high electronegativity
b) presence of stable half-filled electronic configuration
Stability of hydrides of group 16 elements
a) increases down the group
b) decreases down the group
c) all hydrides are equally stable
d) none of the above
The lowest boiling point of helium is due to its
a) Inertness
b) Gaseous nature
c) Weak van der Waals force between atoms
d) electronic configuration
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
Which statement correct about halogens?
a) They are all diatomic and form univalent ions.
b) They are all capable of exhibiting several oxidation states.
c) They are all diatomic and form diatomic ions.
d) They are all reducing agents.
which is not the property of dioxygen gas
a) Dioxygen is a colourless and odourless gas.
b) Dioxygen is paramagnetic.
c) Dioxygen is diamagnetic.
d) Dioxygen is soluble in water which support aquatic life.
The idea that promoted to Bartlett to prepare first ever compound of Noble gases was
a) Low bond dissociation enthalpy of F-F bond in \(F_2\).
b) High bond enthalpy of Xe-F bond.
c) Ionization enthalpies of \(O_2\) and Xe are almost same.
d) None of the above.
Why is Helium used in divers' tank but not hydrogen gas?
a) Helium is lighter than hydrogen.
b) Helium is inert to any chemical reactions.
c) Helium is cheaper.
d) Helium is easy to get from market.
In the periodic table of the elements, the phrase “middle row anomaly” refers to
a) Middle elements of periodic table are transition metals.
b) Middle element of each group is unstable.
c) the relative instability of bromine oxides compared to the other halogen oxides.
d) The higher oxides of halogens tend to be more stable than the lower ones.
The reaction R-Br + NaCN → R – CN + NaBr is an example of –
(a) Elimination Reaction.
(b) Nucleophilic Substitution.
(c) Electrophilic Substitution.
(d) Oxidation Reduction.
Which of the following is not true about the ionic solids?
(A) Bigger ions form the close packed structure.
(B) Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.
(C) Occupation of all the voids is not necessary.
(D) The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.
An alcohol X when treated with hot conc. \(H_2\)\(SO_4\) gave an alkene Y with formula \(C_4\)\(H_8\). This alkene on ozonolysis gives single product with molecular formula \(C_2\)\(H_4\)O. The alcohol is
(a) butan-1-ol.
(b) butan-2-ol.
(c) 2-methylpropan-1-ol.
(d) 2,2-dimethylbutynal-1-oI.
Which of the following is an example of vic-dihalide?
(a) Dichloromethane.
(b) 1,2-dichloroethane.
(c) Ethylidene chloride.
(d) Allyl chloride.
Identify the correct order of acidic strength for H-X
a) HCl > HBr > HI.
b) HCl > HI > HBr.
c) HI > HCl > HBr.
d) HI > HBr > HCl.
Which statement is incorrect about peptide bond?
(a) C-N bond length in proteins is longer than usual bond length of C-N bond.
(b) Spectroscopic analysis shows planar structure of -CO-NH- group
(c) C-N bond length in proteins is smaller than usual bond length of C-N bond
(d) None of the above