Question

Which is the correct definition of an acid anhydride?

A: an acid that has donated a proton
B: the neutralization product of an acid and a base
C: a compound that reacts with water to form an acid
D: a compound that gives off water to become an acid

Answer 1

An acid anhydride is a compound that reacts with water to produce an acid; these are usually inorganic nonmetal oxides.

Step-by-step explanation:

The correct definition of an acid anhydride is C: a compound that reacts with water to form an acid. Acid anhydrides are inorganic nonmetal oxides that, when reacting with water, yield acidic solutions. These reactions are typically exothermic, releasing energy in the form of heat.

For example, when sulfur trioxide (SO3) reacts with water, it forms sulfuric acid (H2SO4):

SO3 + H2O → H2SO4

The term 'anhydride' means 'without water', so an acid anhydride thus refers to an oxide that could form an acid if water were added.