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

1. Metallic hydrides                           

2. Ionic hydrides

3. Molecular hydrides                       

4. Water

${}_1{}^2\mathrm{H}$ stands for –

(1) Protium                               

(2) Heavy water

(3) Deuterium                           

(4) Tritium

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

100 ml of a sample of hard water required 25.1 ml of 0.02 (N) ${\mathrm{H}}_2{\mathrm{SO}}_4$ for complete reaction. What is the hardness of the given water sample ? (sp. gravity of given water sample = 1 gm/ml)

(A) 200 ppm                                 

(B) 250 ppm

(C) 251 ppm                                 

(D) 258 ppm

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

50 lit of hard water of 120 ppm temporary hardness is mixed with 1.62 kg of $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2,$ what is the hardness of the resulting water ? (The sp. gr. of hard water = 1 gm/ml)

(A) 8.088 × 10⁵ ppm                               

(B) 8.088 × 10⁴ ppm

(C) 80 ppm                                             

(D) 808 ppm

Commercially ${\mathrm{H}}_2{\mathrm{O}}_2$ is now prepared by –

(A) Action of ${\mathrm{H}}_2{\mathrm{SO}}_4$ on barium peroxide

(B) Action of ${\mathrm{H}}_2{\mathrm{SO}}_4$ on sodium peroxide

(C) Electrolysis of ${\mathrm{H}}_2{\mathrm{SO}}_4$

(D) By burning hydrogen in excess of oxygen

Hydrogen peroxide does not

(1) Liberate iodide from $\mathrm{KI}$

(2) Turn the titanium salt yellow

(3) Give silver peroxide with moist silver oxide

(4) Turn the mixture of aniline, ${\mathrm{KClO}}_3$ and dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ violet

A sample of hard water was found to contain 68 ppm of ${\mathrm{CaSO}}_4$ and 19 ppm of ${\mathrm{MgCl}}_2$. Its total hardness is –

(1) 70 ppm                             

(2) 50 ppm

(3) 20 ppm                             

(4) 100 ppm

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