Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9 respectively. Which solution is strongly acidic?

B

The correct answer is option 2.  B.

The pH scale is a measure of the acidity or alkalinity of a solution. It ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, and values above 7 indicate alkalinity. The lower the pH value, the stronger the acidity of the solution.

In the given options:
Solution A has a pH of 4, indicating it is acidic but not strongly acidic.
Solution B has a pH of 1, which is very low on the pH scale, indicating a highly acidic solution. This makes solution B strongly acidic.
Solution C has a pH of 11, which is alkaline, not acidic.
Solution D has a pH of 7, which is neutral.
Solution E has a pH of 9, indicating it is slightly alkaline but not strongly acidic.

Therefore, among the options, Solution B is the one that is strongly acidic with a pH of 1.