A cloth strip dipped in onion juice is used for testing a liquid 'X'.The liquid 'X' changes its odour. Which type of an indicator is onion juice ?The liquid 'X' turns blue litmus red. List the observations the liquid 'X' will show on reacting with the following : (a) zinc granules (b) solid sodium carbonate write the chemical equation for the reaction involved.

A cloth strip dipped in onion juice is used for testing a liquid 'X'.T

1.	A cloth strip dipped in onion juice is used for testing a liquid 'X'.The liquid 'X' changes its odour. Which type of an indicator is onion juice ?The liquid 'X' turns blue litmus red. List the observations the liquid 'X' will show on reacting with the following : (a) zinc granules (b) solid sodium carbonate write the chemical equation for the reaction involved.
Answer» Solution :• Onion juice CONTAINS only factory INDICATOR it changes it odour when an ACID or alkali is added to it. • As the liquid X turns blue litmus red it is an acid. (a) `Zn + 2HCl rarr ZnCl_(2) + H_(2) uarr` Hydrogen gas is evolved in this reaction. (B) `Na_(2)CO_(3) + 2HCl rarr 2NaCl + CO_(2) + H_(2)O` An effervescence takes place and `CO_(2)` gas is evolved which turns lime water milky.