Question

How much
(a) potassium nitrate and
(b) mercuric oxide
must be heated to yield as much oxygen as would be obtained from 35g of KclO3

Answer 1

Given:

Oxygen is obtained from 35 gm of KClO3

To Find:

Amount of potassium nitrate and  mercuric oxide heated to produce same amount of oxygen

Calculation:

Oxygen in 122.5 gm KClO3 = 48 gm

⇒ Oxygen in 35 gm KClO3 = (48/122.5) × 35 = 13.71 gm (approx)

- Thermal decomposition of KNO3 is:

2 KNO3 → 2 KNO2 + O2

⇒ Amount of KNO3 required to produce 32 gm oxygen = 202 gm

⇒ Amount of KNO3 required to produce 13.71 gm oxygen

    = (202/32) × 13.71 = 86.54 gm

- Thermal decomposition of HgO is:

2 HgO → 2 Hg + O2

⇒ Amount of HgO required to produce 32 gm oxygen = 433 gm

⇒ Amount of HgO required to produce 13.71 gm oxygen

     = (433/32) × 13.71 = 185.51 gm

- So, the amount heated to yield as much oxygen as would be obtained from 35 gm of KClO3 is:

(a) 86.54 gm potassium nitrate

(b) 185.51 gm mercuric oxide