The process of removing permanent hardness of water by adding washing soda is based on: MCQ with Answer and Explanation

Explanation:
pH = -log[H⁺] = -log(10⁻⁴) = 4. The solution is acidic. pOH = 14 - pH = 10, so [OH⁻] = 10⁻¹⁰ M. pH scale ranges 0-14 (typically). pH < 7 acidic, pH = 7 neutral, pH > 7 basic. Pure water has [H⁺] = 10⁻⁷ M, pH=7.

Explanation:
Finely divided nickel is used as catalyst for hydrogenation of unsaturated oils to saturated fats. Platinum and palladium can also be used but are more expensive. The reaction occurs at about 150°C with H₂ gas. Nickel catalyst is prepared by reducing NiO with H₂. This is an important industrial process for making margarine and shortenings.

Explanation:
Faraday constant (F) = 96485 C/mol, approximately 96500 C/mol. It is the magnitude of electric charge per mole of electrons. Charge on one electron = 1.602 × 10⁻¹⁹ C, multiplied by Avogadro's number gives F. Used in electrolysis calculations: mass deposited = (Q × M)/(n × F).