Question

A piece of calcium metal is placed in water. A reaction takes place in which bubbles of hydrogen gas are seen. After the reaction stops, the solution is tested for its colour, temperature and action with litmus solution. Select the correct observation

• A. The solution is hot, milky white and turns red litmus blue
• B. The solution is hot, colourless and turns blue litmus red
• C. The solution is cold, milky and turns blue litmus red
• D. The solution is cold, colourless and does not change the colour of litmus.

Answer 1

The correct option is A The solution is hot, milky white and turns red litmus blue

Calcium reacts with water to form calcium hydroxide and hydrogen. It is an exothermic process so the solution formed is hot. Calcium hydroxide is basic in nature so it turns red litmus blue. When carbon dioxide is passed through lime water it turns milky.