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Railways PYQCBT 1 2016

RRB NTPC · Question 5

What is the common name of the solution of calcium hydroxide?

  1. Lime water

  2. Diet soda

  3. Salt solution

  4. Vinegar

Show answer & explanation

Answer: (A) Lime water

Explanation

A clear solution of calcium hydroxide, Ca(OH)₂, in water is called lime water. It turns milky when carbon dioxide is bubbled through it, because insoluble calcium carbonate forms; this is the standard test for CO₂.