Since primary school we've been checking for the qualities known as acidity and alkalinity with litmus paper.

When investigating the pH (acidic, neutral, alkaline) of a liquid, don't soak the litmus paper completely in the liquid but just put the end of the paper in it.

Acid soil is neutralised by ash.

I read an article about acid rain yesterday.

Acid rain is not a natural phenomenon.

Acid rain in drinking water affects human health.

Acid fruits like pineapples and lemons are sour.

The decay of the shrine is due, in part, to acid rain.

The auditorium is terribly stained. It is, in part, due to acid rain.

The outside walls of the auditorium are terribly stained. It is, in part, due to acid rain.

The fish are dying, the Canadians say, because of what's known as acid rain.

The ocean is becoming more acidic.

When the ocean absorbs a lot of CO₂, the water becomes more acidic.