A student was working in a chemistry laboratory. He found that a bottle contained a white powdery substance but half of the label on the bottle was torn. The part of label still sticking to the bottle had NaH written on it. The student took this powdery substance in a test-tube and added dil. HCl to it. A gas was evolved which extinguished a burning match-stick.
(a) Name the gas evolved.
(b) Write the formula of white powdery substance.

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Solution

When dilute hydrochloric acid is mixed with that salt a gas is produced which extinguished a burning match-stick that means the gas produced is carbon dioxide.
So, the salt must be sodium bicarbonate.
$HCl + {NaHCO}_{3} \to NaCl + H_{2} O + {CO}_{2}$

(a) Hence, the gas produced is carbon dioxide.

(b) White powdery salt is sodium bicarbonate(NaHCO₃).

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