Mark ‘T’ if the statement is true and ‘F’ if it is false:

  1. Nitric acid turn red litmus blue. (T/F)
  2. Sodium hydroxide turns blue litmus red. (T/F)
  3. Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water. (T/F)
  4. Indicator is a substance which shows different colours in acidic and basic solutions. (T/F)
  5. Tooth decay is caused by the presence of a base. (T/F)

 

Answer:

(a)

  • Nitric acid is acidic in nature.
  • Acids turn blue litmus red , and produce no colour change in red litmus .
  • Hence it does not change the colour of red litmus.

Therefore, the statement is false.

(b) 

  • Sodium Hydroxide is basic in nature 
  • Bases turn red litmus blue , and produce no colour change in blue litmus .
  • Hence it does not change the colour of blue litmus.

Therefore, the statement is false.

(c)

  • Sodium hydroxide is a base and hydrochloric acid is an acid.
  • They neutralise each other and form salt and water.

Therefore, the statement is true.

(d) 

  • Indicator is a substance which is used to indicate the nature of a chemical.
  • It is used this way because it shows different colours in acidic and basic solutions .

Therefore, the statement is true.

(e) False

  • Tooth decay is caused due to the presence of acids .
  • Our body releases acids to digest food in our mouth, which if left over, causes damage to the tooth and tooth decay .

Therefore, the statement is false.

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CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo