Correct Answer - Option 2 : 62.5 ml
Given:
The solution is 500 ml
Calculation:
Firstly, alcohol in solution = 500 × (10/100) = 50 ml
⇒ Now water become 80% of the solution = 500 - 50 = 450
⇒ New total solution = (450/80) × 100 = 562.5
⇒ Now added alcohol = 562.5 - 500 = 62.5 ml
∴ The required result will be 62.5 ml.