Question

When a student added a few drops of methyl orange indicator to a colourless solution, the solution turned red. Which of the following should he add in excess so that the colour changes to yellow ?
(1) NaOH solution
(2) H₂SO₄ solution
(3) Lemon juice
(4) Vinegar solution

Answer 1

Methyl orange turns red in the acidic solution and to convert it to the yellow colour, student needs to add excess of basic solution because in basic solution methyl orange shows yellow colour. So, out of given options, sodium hydroxide is a strong base which can change the colour of solution to yellow.

Hence, the correct answer is option 1.