Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number?
(a) 25
(b) 26
(c) 27
(d) 24
(a) 25
(b) 26
(c) 27
(d) 24
(b) 26
Explanation : It is formed by the loss of 3 electrons, the configuration of element X is [Ar] 3d⁶ 4s². Therefore, Atomic number = 26.
Explanation : It is formed by the loss of 3 electrons, the configuration of element X is [Ar] 3d⁶ 4s². Therefore, Atomic number = 26.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
What are the transition elements ? Write two characteristics of the transition elements.
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number.
Explain the following observation :
Most of the transition metal ions exhibit characteristic colour in aqueous solution.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
When Cu²⁺ ion is treated with KI, a white precipitate is formed. Explain the reaction with the help of chemical equation.
A compound is formed by two elements M and N. The element N forms ccp lattice and atoms of M occupy two atoms an Mercury 1/3rd of tetrahedral voids. What is the formula of the compound?
(A) \(MN_2\)
(B) \(M_2\)\(N_3\)
(C) \(M_3\)\(N_2\)
(D) \(M_2\)\(N_2\)
Acetone and carbon disulphide form binary liquid solution showing positive deviation from Raoult’s law. The normal boiling point (Tb) of pure acetone is less than that of pure \(CS_2\). Pick out the
incorrect statement among the following-
(a) Boiling temperature of the mixture is always less than the boiling temperature of acetone
(b) Boiling temperature of Azeotropic mixture is always less than the boiling temperature of acetone
(c) When a small amount of \(CS_2\) (less volatile component) is added to an excess of acetone boiling point
of the resulting mixture increases
(d) A mixture of \(CS_2\) and \(CH_3\)\(COCH_3\) can be completely separated by simple fractional distillation
An unknown alcohol is treated with “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism?
(a) Tertiary alcohol by SN2.
(b) Secondary alcohol by SN1.
(c) Tertiary alcohol by SN1.
(d) Secondary alcohol by SN2.
Which is incorrect statement.
a) Oxygen is the most abundant of all the elements on earth
b) Organic materials such as eggs, proteins, garlic, onion, mustard, hair and wool contain sulphur
c) Selenium and tellurium are found as metal selenides and tellurides in sulphide ores
d) Livermorium is a natural radioactive element
One mole of ethyl acetate on treatment with an excess of \(LiAlH_4\) in dry ether and subsequent acidification produces
(a) 1 mole acetic acid + 1 mole ethyl alcohol.
(b) 1 mole ethyl alcohol + 1 mole methyl alcohol.
(c) 2 moles of ethyl alcohol.
(d) 1 mole of 2-butanol.
A compound X with the molecular formula \(C_2\)\(H_8\)O can be oxidised to another compound Y whose molecular formulae is \(C_3\)\(H_6\)\(O_2\). The compound X may be
(a) \(CH_3\)\(CH_2\)\(OCH_3\).
(b) \(CH_3\)\(CH_2\)CHO.
(c) \(CH_3\)\(CH_2\)\(CH_2\)OH.
(d) \(CH_3\)\(CHOHCH_3\).
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number?
(a) 25
(b) 26
(c) 27
(d) 24