Question

A blue litmus paper was first dipped in dilute HCl and then in dilute NaOH solution. It was observed that the colour of litmus paper : (a) changed first to red then to colourless (b) changed first to red then to blue (c) changed blue to colourless (d) remained blue in both solutions.

Answer 1

Blue litmus paper change into red when it dipped in acid. And when it dipped in base ít change into blue.

So Option B is correct.

Answer 2

The answer for the given question is (B). changed first to "red then to blue "

Answer - (Option B)

Explanation:

• A ‘blue litmus paper’ when first dipped in the “dilute HCl” will turn into 'red colour'.
• Then when dipped in “dilute NaOH solution”, it will turn into blue again.
• Depending upon the 'pH' of a solution, a ‘litmus paper’ will change its color.
• A red litmus paper will turn blue when dipped in ‘alkaline solutions’ and will retain its red color when dipped in acidic solutions.
• A 'blue litmus paper' will turn red when dipped in ‘acidic solutions’ and will remain blue in ‘alkaline solutions’.