Which of the following substances cause temporary hardness in water? 1. Mg(HCO₃)₂ 2. Ca(HCO₃)₂ 3. CaCl₂ 4. MgSO₄ Select the correct answer using the code given below.

Which one of the following is not correct?

Which one of the following is also called Stranger Gas?

Which of the following remains in a solid state at normal temperature?

Which one of the following fuels causes minimum air pollution?

Which of the following pair of gases is used for the respiratory activities of divers?