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Acids, Bases and Salts — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceAcids, Bases and Salts3 Marks
Question
Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal of hardness of water and a gas C is evolved. The gas C when passed through lime water, turns it milky. Identify A, B and C.
✓

Answer

Salt which is used in bakery product is baking soda or sodium hydrogen carbonate. On heating of baking soda, sodium carbonate is formed with evolution of carbon dioxide gas.$2\text{NaHCO}_3\rightarrow\text{Na}_2\text{CO}_3+\text{H}_2\text{O + CO}_2\uparrow$
Sodium carbonate is used to remove hardness of water. Another product is carbon dioxide gas that gives lime test in which it turns lime water milky. Thus, $A = NaHCO _3 ; B = Na _2 CO _3$ and $C = CO _2$.

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