Question

Which of the following set of substances contain acids?

• A. Grapes, lime water
• B. Vinegar, soap
• C. Curd, milk of magnesia
• D. Curd, vinegar

Answer 1

The correct option is D

Curd, vinegar

Explanation for correct option:

D. Curd, vinegar

Acids:

• Acids are substances that donate a proton ${\mathrm{H}}^{+}$.
• Acid changes blue litmus to red.
• Examples of Acids are Hydrochloric acid $\left(\mathrm{HCl}\right)$ as well as Acetic acid $\left({\mathrm{CH}}_3\mathrm{COOH}\right)$.
• Curd contains Lactic acid with the chemical formula ${\mathrm{C}}_3{\mathrm{H}}_6{\mathrm{O}}_3$while vinegar has acetic acid in it.

Explanation for incorrect options:

A. Grapes, lime water

• Grapes contain tartaric as well as L-malic acid.
• Lime water is basic in nature.

B. Vinegar, soap

• Vinegar has acetic acid in it.
• Soap is basic in nature.

C. Curd, milk of magnesia

• Curd contains Lactic acid with the chemical formula ${\mathrm{C}}_3{\mathrm{H}}_6{\mathrm{O}}_3$.
• Milk of magensia conatins magenisum hydroxide $\mathrm{Mg}{\left(\mathrm{OH}\right)}_2$.

Hence, the correct option is D i.e. Curd, vinegar.