Question

The painful sting of a honey bee is due to the injection of methanoic acid. Which of the following substances would be the safest to apply on the skin to neutralize the sting?

• A. Lemon juice $(\mathrm{pH}=4)$
• B. Concentrated $\mathrm{HCl}$ $(\mathrm{pH}=1)$
• C. Baking soda $(\mathrm{pH}=8)$
• D. Clean-up liquid $(\mathrm{pH}=14)$

Answer 1

The correct option is C

Baking soda $(\mathrm{pH}=8)$

Explanation for the correct option:

Option (C)

• When a honey bee stings, Methanoic acid or Formic acid $\left(\mathrm{HCOOH}\right)$is injected which gives us a painful experience.
• To neutralize it, we could simply use a base (pH value should be greater than 7).
• Among the given options, Baking soda (pH=8) would be the safest to apply to the skin to neutralize the sting.
• A paste of baking soda and water can help with a variety of insect bites and stings.
• Baking soda is the safest to apply to the skin because it can neutralize bee venom, reducing itching and swelling.
• Reaction: $\underset{(\mathrm{Formic}\mathrm{acid})}{\mathrm{HCOOH}\left(\mathrm{aq}\right)}+\underset{(\mathrm{Baking}\mathrm{soda})}{{\mathrm{NaHCO}}_3\left(\mathrm{aq}\right)}\to \underset{(\mathrm{Sodium}\mathrm{formate})}{\mathrm{HCOONa}\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{Water}\right)}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}+\underset{(\mathrm{Carbon}\mathrm{dioxide})}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$

Explanation for the incorrect options:

Option (A): Lemon juice is acidic with a pH value of 4, and it will not neutralize the formic acid.

Option (B): Hydrochloric acid with a pH value of 1, is highly acidic and it will not neutralize the formic acid. Instead, it will cause burn on the skin because of its highly corrosive nature.

Option (D): Formic acid is a weak acid, and to neutralize it the safest option is to use a weak base i.e., Baking soda (pH=8), and not clean up liquid which is a very strong base pH=14, because it is also slightly corrosive in nature.

Hence, option (C) is correct.