Heavy water is used as

1. moderator in nuclear reactions

2. coolant in nuclear reactions

3. both (1) and (2)

4. none of these

Which of the following pairs of substances on reaction will not evolve gas?

1. Iron, and ${\mathrm{H}}_2{\mathrm{SO}}_4$ (aq)

2. Iron, and steam

3. Copper, and HCl(g)

4. Sodium, and ethyl alcohol

Which transition metal is used for the reduction of steam to hydrogen?

1. Mg

2. Fe

3. Sc

4. Pt

The percentage by weight of Hydrogen of $H_2{O}_2$ is:

(1) 5.88

(2) 6.25

(3) 25

(4) 50

Hard water can be produced by -

(1) Saturation of water with CaSO₄

(2) Addition of $N{a}_{2}S{O}_4$  to water

(3) Saturation of water with CaCO₃

(4) Saturation of water with MgCO₃

When zeolite (hydrated sodium aluminium silicate) is treated with hard water the sodium ions are exchanged with:

(1) $H^{+}ions$

(2) $C{a}^{2+}$ ions

(3) $S{O}_4^{2-}$ ions

(4) $O{H}^{-}$ ions

The volume strength of 1.5 N H${}_2$O${}_2$ solution is:

(1) 4.8

(2) 8.4

(3) 3.0

(4) 8.0

Under what condition of temperature and pressure the formation of atomic hydrogen from molecular hydrogen will be favoured most?

(1) High temperature and high pressure

(2) Low temperatureand low pressure 

(3) High temperatureand low pressure 

(4) Low  temperature and high pressure

The hair dyes availabe in the market generally contain two bottles, one containing the

dye and the other hydrogen peroxide. Before applying the dye, the two solutions are

mixed. The hydrogen peroxide:

(1) is added to dilute the solution of the dye

(2) oxidises the dye to give the disired colour

(3) reduces the dye to given the desired colour

(4) acidifies the solution of the dye

The amount of $H_2{O}_2<mspace\; width="1em"></mspace>$ present in 1 L of 1.5 N $H_2{O}_2<mspace\; width="1em"></mspace>$ solution is:

1. 2.5 g

2. 25 g

3. 3.0 g

4. 8.0 g