The change in colour of the moist litmus paper in the given set up is due to
- presence of acid
- presence of base
- presence of H⁺(aq) in the solution
- presence of Litmus which acts as an indicator
- i and ii
- Only ii
- Only iii
- Only iv
- Litmus is an indicator that indicates the presence of acids or bases by changing its colour.
- When an acid is added to litmus, it changes its colour to red .
- When a base is added it changes its colour to blue .
- In the figure, conc H 2 SO 4 is being added to a tube containing NaCl .
The following reaction takes place:
- Here, HCl is liberated in the form of a gas .
- Since HCl is an acid, the litmus turns red due to the HCl gas.
- The acid causes the solution to have H+ ions .
Therefore, the correct answer is (c) only (iii)