The method used to remove the temporary hardness of water is-

1. Synthetic resins method

2. Calgon's method

3. Clark's method

4. Ion-exchange method

Hydrogen adsorbed on palladium is known as:

(1) atomic H

(2) nascent H

(3) occluded H

(4) heavy H

30ml of a ${\mathrm{H}}_2{\mathrm{O}}_2$ solution after acidification required 30ml of $\mathrm{N}/10$ ${\mathrm{KMnO}}_4$ solution for complete oxidation. Calculate the percentage and volume strength of ${\mathrm{H}}_2{\mathrm{O}}_2$ solution.

(A) 2.17%, 2.56                         

(B) 0.17%, 0.56

(C) 5.12%, 3.16                         

(D) 3.12%, 0.86

What mass of hydrogen peroxide is present in 2 litre solution of 4M strength ? Calculate the volume of oxygen at S.T.P. liberated upon complete decomposition of 400 ${\mathrm{cm}}^3$ of the above solution.

(A) 172g, 0.92 L                                   

(B) 272g, 1.32 L

(C) 272g, 17.92 L                                 

(D) 172g, 15.14 L

A certain sample of hydrogen peroxide is 1.5M solution. It is to be labelled as X volumes. Calculate the value of X.

(1) 16.8 L                             

(2) 11.8 L

(3) 5.3 L                               

(4) 6.2 L

A mixture of hydrazine $\left({\mathrm{N}}_2{\mathrm{H}}_4\right)$ and $58-60\%$ solution of ${\mathrm{H}}_2{\mathrm{O}}_2$ is used as.

(1) Antiseptic                     

(2) Fertilizer

(3) Rocket fuel                   

(4) None

A substance gives off ${\mathrm{O}}_2$ when heated, turns an acid solution of $\mathrm{KI}$ violet, and reduces acidified ${\mathrm{KMnO}}_4$. The substance is –

1. ${\mathrm{SO}}_3$                            

2. ${\mathrm{KNO}}_3$

3. ${\mathrm{H}}_2{\mathrm{O}}_2$                          

4. All of these

In which of the following compounds, hydrogen exists in the atomic state –

1. Metallic hydrides                           

2. Ionic hydrides

3. Molecular hydrides                       

4. Water

The colour of hydrogen is –

1. Blue                           

2. Yellow

3. Orange                       

4. No colour

The best explanation for not placing hydrogen with the group of alkali metals or halogens is.

1. Hydrogen can form compounds with all other elements

2. Hydrogen is much lighter element than the alkali metals or the halogens

3. The IE of hydrogen is too high for group of alkali metals but too low for halogen group

4. None of these