Question

Assertion: Sodium carbonate is an acidic salt.
                   Reason: It gives a basic solution in water.
a.) Both assertion and reason are correct and reason is the correct explanation of assertion.
b.) Both assertion and reason are correct and reason is not the correct explanation of assertion.
c.) Assertion is correct but reason is incorrect.
d.) Assertion is incorrect but reason is correct.

Answer 1

Hint: Acids- Substances producing ${ H }^{ + }$ ions when dissolved in water.
Bases- Substances producing ${ OH }^{ - }$ ion in its water solution


Complete Solution :
 Sodium carbonate is basic in nature with pH= ${ 10.3 }$ .It is used as a water softener in domestic use.
When sodium carbonate reacts with water then sodium hydroxide and carbonic acid are formed.
- The following reaction will take place:
${ Na }_{ 2 }{ CO }_{ 3 }{ +H }_{ 2 }{ O\rightarrow NaOH+H }_{ 2 }{ CO }_{ 3 }$
- Hence, sodium carbonate is a strong base while acid is weak, so the solution is basic, not acidic.
So, the correct answer is “Option D”.

Additional Information:
Sodium carbonate is used for the production of the following materials.
- Sodium carbonate is essential to the production of glass. This market is composed of manufacturers of glass packaging (bottles and other containers), commercial, residential, and automobile windows, mirrors, fiberglass, television tubes, lighting ware, tableware, glassware, and laboratory glass.
- Detergents: Dry laundry detergents typically contain anywhere from 20% to 80% Sodium carbonate. Sodium carbonate also often is the prime alkali used to make phosphates and silicates for detergent applications.
- Water Treatment: Sodium carbonate can be used to control pH (acidity) levels in water and also provides the sodium ion needed for water softening.

Note: It is important to understand the difference between sodium carbonate and sodium bicarbonate. Sodium carbonate is an alkali, however, sodium bicarbonate is mild acid. The two compounds have different properties and uses as well. So always remember to read the question twice before starting to solve the question.