Salts (Overview) MCQs Quiz | Class 10

This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. It focuses on the topic of Salts, specifically their formation by neutralization reactions and common examples found in the laboratory and daily life. Test your understanding, check your score, and download the solution PDF.

Understanding Salts: Nature and Behaviour

In Chemistry, a salt is an ionic compound composed of two groups of oppositely charged ions. The positively charged ion is called a cation (usually a metal or ammonium ion), and the negatively charged ion is called an anion (non-metal or polyatomic ion). Salts are typically formed by the neutralization reaction between an acid and a base.

1. Formation by Neutralization

The most fundamental method of salt formation is the reaction between an acid and a base. This reaction yields salt and water.

General Equation: Acid + Base → Salt + Water

Example: Hydrochloric acid reacts with Sodium hydroxide to form Sodium chloride (common salt) and water.

HCl + NaOH → NaCl + H2O

2. Families of Salts

Salts having the same positive or negative radicals belong to a family. For example:

  • Sodium Salts: NaCl, Na2SO4, NaNO3 (contain Na+).
  • Chloride Salts: NaCl, KCl, NH4Cl (contain Cl).

3. pH Nature of Salts

Salts are not always neutral. Their pH depends on the strength of the parent acid and base:

Parent Acid Parent Base Nature of Salt Example
Strong Strong Neutral (pH = 7) NaCl, K2SO4
Strong Weak Acidic (pH < 7) NH4Cl
Weak Strong Basic (pH > 7) Na2CO3

4. Common Salts in Daily Life

  • Common Salt (NaCl): Essential for food and a raw material for various chemicals like NaOH, baking soda, etc.
  • Bleaching Powder (CaOCl2): Used for disinfecting water and bleaching textiles.
  • Baking Soda (NaHCO3): Used in cooking and as an antacid.
  • Washing Soda (Na2CO3.10H2O): Used for cleaning and removing permanent hardness of water.
  • Plaster of Paris (CaSO4.1/2H2O): Used for supporting fractured bones.

Quick Revision List

  • Rock Salt: Large crystals of impure NaCl, often brown due to impurities.
  • Brine: Concentrated aqueous solution of sodium chloride.
  • Water of Crystallization: Fixed number of water molecules present in one formula unit of a salt (e.g., Blue Vitriol is CuSO4.5H2O).

Extra Practice Questions

  1. Why does an aqueous solution of acid conduct electricity?
  2. What is the chemical name of Plaster of Paris?
  3. Name the salt formed when Sulphuric acid reacts with Potassium hydroxide.
  4. What happens when Blue Vitriol is heated?
  5. Is Ammonium Chloride an acidic or basic salt?