Which of the following compounds is used for water softening?

1.  ${\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2$

2.  ${\mathrm{Na}}_3{\mathrm{PO}}_4$

3.  ${\mathrm{Na}}_6{\mathrm{P}}_6{\mathrm{O}}_{18}$

4.  ${\mathrm{Na}}_2{\mathrm{HPO}}_4$

Elements of which of the following group(s) of periodic table do not form hydrides.

1.  Groups 7, 8, 9

2.  Group 13

3.  Groups 15, 16, 17

4.  Group 14

Only one element of ________ forms hydride.

1. Group 6

2. Group 7

3. Group 8

4. Group 9

Match the terms in Column I with the relevant item in Column II.
              Column I                                       Column II
(1) Electrolysis of water produces                  (a) Atomic reactor
(2) Lithium aluminium hydride is used as       (b) Polar molecule
(3) Hydrogen chloride is a                             (c) Recombines on metal
                                                                       surface to generate high temperature
(4) Heavy water is used in                            (d) Reducing agent
(5) Atomic hydrogen                                    (e) Hydrogen and oxygen

1. (1)$\Rightarrow$e, (2)$\Rightarrow$d, (3)$\Rightarrow$b, (4)$\Rightarrow$a, (5)$\Rightarrow$c

2. (1)$\Rightarrow$b, (2)$\Rightarrow$c, (3)$\Rightarrow$a, (4)$\Rightarrow$d, (5)$\Rightarrow$e

3. (1)$\Rightarrow$a, (2)$\Rightarrow$d, (3)$\Rightarrow$e, (4)$\Rightarrow$b, (5)$\Rightarrow$c

4. (1)$\Rightarrow$d, (2)$\Rightarrow$c, (3)$\Rightarrow$a, (4)$\Rightarrow$b, (5)$\Rightarrow$e

Match the items in Column I with the relevant item in Column II.

1. (1) → (b), (d) (2) → (c) (3) → (a), (c)

2. (1) → (c), (d) (2) → (b) (3) → (a), (c)

3. (1) → (b), (a) (2) → (a) (3) → (d), (c)

4. (1) → (a), (c) (2) → (d) (3) → (a), (b)

The ionisation energy of hydrogen is high as compared to alkali metals because of

1. One electron in outermost shell

2. Small size

3. One proton in its nucleus

4. No Neutron

High purity dihydrogen is obtained by

1. Warm aqueous barium hydroxide

2. Brine solution

3. Acidified sulphate solution

4. Water gas

Hardness  of water  cannot  be removed by

1. Treating with washing soda
2. Boiling
3. Adding calgon
4. Addition of chlorine

H₂O₂ can be obtained when following reacts with H₂SO₄ except with

Which is not a polymeric/dimeric hydride?

1. ${\mathrm{BeH}}_2$

2. ${\mathrm{MgH}}_2$

3. ${\mathrm{BH}}_3$

4. $\mathrm{NaH}$