Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper. What would be the colour obtained? (You may use colour guide given in Figure 2.2 

Fig 2.2.jpg

(A) Red

(B) Yellow

(C) Yellowish green

(D) Blue




  • HCl is a strong acid and NaOH is a strong base . So, when equal volumes of both are mixed, they undergo neutralization reaction to form salt and water.
  • Therefore, the pH of the resulting solution is near neutrality i.e. 7

Acidic, Basic and Neutral Salts-01.jpg

As is clear from the figure given above, the color corresponding to pH 7 is yellowish green


So, the correct option is (c) yellowish green

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CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo