Read the following question and answer:
Sara took \(2\ mL\) of dilute \(NaOH\) solution in a test tube and added two drops of phenolphthalein solution to it. The solution turned pink in colour. She added dilute \(H_2SO_4 \) to the above solution drop by drop until the solution in the test tube became colourless. \(40\) drops of dilute \(H_2SO_4\) were used for the change in colour from pink to colourless. When Sara added a drop of \(NaOH\) to the solution, the colour changed to back to pink again. Sara now tried the activity with different volumes of \(NaOH\) and recorded her observation in the table given below:
| S. No | Volume of dil. \(NaOH\) taken (\(mL\)) |
Drops of dil. \(H_2SO_4\) used |
| 1 | 2 | 20 |
| 2 | 3 | 30 |
| 3 | 4 | 40 |
Answer the following questions based on the above information:
1. What was the initial colour of the solution when Sara added phenolphthalein to \(NaOH\)?
2. Sara takes \(10\) drops of dilute \(H_2SO_4\) in the test tube and adds two drops of phenolphthalein solution to it. Then, she adds \(NaOH\) dropwise. Sara observes a change in colour after adding \(20\) drops of \(NaOH\). What change in colour would she observe?