A compound "X", upon reaction with H₂O, produces a colourless gas "Y" with a rotten fish smell.  Gas 'Y' is absorbed in a solution of CuSO₄ to give Cu₃P₂ as one of the products. The compound 'X' will be:

1. Ca₃P₂

2. ${\mathrm{NH}}_4\mathrm{Cl}$

3. ${\mathrm{As}}_2{\mathrm{O}}_3$

4. Ca₃(PO₄)₂

The cation of alkali metals are found as M(H₂O)⁺_n in H₂O.

The value of 'n' is maximum for -

1. Na⁺

2. K⁺

3. Rb⁺

4. Li⁺

1 mole of substance (X) was treated with an excess of water. 2 moles of readily combustible gas were produced along with solution which when reacted with CO₂ gas produced a white turbidity. The substance (X) could be

(1) Ca

(2) CaH₂

(3) Ca(OH)₂

(4) Ca(NO₃)₂

A chloride dissolves appreciably in cold water. When placed on a Pt-wire in Bunsen flame, no distinctive colour is noticed. Cation present is

(1) Mg²⁺

(2) Ba²⁺

(3) Pb²⁺

(4) Ca²⁺

Fire extinguisher contains NaHCO₃ and the compound (X). The compound (X) may be

(1) CH₃COOH

(2) NaOH

(3) C₆H₅OH

(4) Any of these

Alkali metals do not form nitride on reaction with N₂, whereas lithium forms Li₃N, because

(1) High ionisation energy of Li

(2) High lattice energy of Li₃N

(3) High sublimation energy of Li

(4) High covalent nature of Li₃N

All group-2 metals dissolve in liquid ammonia to produce a bright blue colour. The colour is due to

1. A change in the structure of ammonia

2. d-d transition

3. The spectrum of the solvate electrons

4. An electronic transition from a lower to a higher energy state

$∆{\mathrm{H}}_{\mathrm{solution}}$ is positive for

I. LiF

II. CsI

III. RbF

IV. KF

(1) I, II, III & IV

(2) II only

(3) I only

(4) I & II only

While moving down the group (in alkaline earth metals) following property increases except

(1) Radius

(2) Solubility of hydroxides

(3) Solubility of sulphates

(4) Thermal stability of carbonates

A chemical compound A is used for water softening to remove temporary hardness. A reacts with Na₂CO₃ to form caustic soda. When CO₂ is bubbled through A it becomes cloudy. The chemical formula of A is

(1) CaO

(2) Ca(OH)₂

(3) Ca(HCO₃)₂

(4) CaCO₃