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Chemical Reactions and Equations — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceChemical Reactions and Equations1 Mark
Question
Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?
  1. It is an endothermic reaction.
  2. It is an exothermic reaction.
  3. The pH of the resulting solution will be more than seven.
  4. The pH of the resulting solution will be less than seven.
  1. 1 and 2
  2. 2 and 3
  3. 1 and 4
  4. 3 and 4
✓

Answer

  1. 2 and 3

Explanation: Slaking of lime is an exothermic reaction which is evident from liberation of heat. Oxides and hydroxides of metals are alkaline. Hence, pH of the resulting solution will be more than 7.

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