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Science · 2023 · 2 marks
CBSE 2023 · Region 1 · Set 1 · Q21
(a) (i) A compound 'X' which is prepared from gypsum has the property of hardening when mixed with proper quantity of water. Identify 'X' and write…
(a)(i)
A compound 'X' which is prepared from gypsum has the property of hardening when mixed with proper quantity of water. Identify 'X' and write its chemical formula.
(ii)
State the difference in chemical composition between baking soda and baking powder.
OR
(b)
Write balanced chemical equation for the reaction that occurs when :
(i)
blue coloured copper sulphate crystals are heated and
(ii)
Sodium hydrogen carbonate is heated during cooking.
Marking-scheme solution
(a)(i)
X: Plaster of Paris/Calcium sulphate hemihydrate.
$\displaystyle \mathrm{CaSO}_{4} \cdot \frac{1}{2} \mathrm{H}_{2} \mathrm{O}$
(ii)
• Baking Soda - $\displaystyle \mathrm{NaHCO}_{3}$ /Sodium hydrogen carbonate/ Sodium bicarbonate
-Baking Powder - A mixture of $\displaystyle \mathrm{NaHCO}_{3} /$ Baking soda + Tartaric acid/any mild edible acid OR
(b)(i)
$\displaystyle \mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O} \xrightarrow{\text { heat }} \mathrm{CuSO}_{4}+5 \mathrm{H}_{2} \mathrm{O}$
(ii)
$\displaystyle 2 \mathrm{NaHCO}_{3} \xrightarrow{\text { heat }} \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}$
All Acids, Bases and Salts questions2023 question paperNCERT solutions: Acids, Bases and SaltsPractice Acids, Bases and Salts →
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CBSE Class 10 Science past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.