Final answer:
To test for different pH values in acid solutions without pH paper, one can use acid-base indicators, which change color at specific pH levels, like phenolphthalein or universal indicator paper.
Step-by-step explanation:
Apart from using litmus or pH paper, a test that can be carried out on acid solutions to check their different pH values is the use of acid-base indicators. These indicators are compounds that change color at certain pH levels due to acid-base equilibria. They are available in various formats, such as solutions or impregnated on paper strips.
For example, a widely known indicator is phenolphthalein, which is colorless in acidic solutions but turns pink in alkaline solutions. Another method is using universal indicator paper that contains a mixture of indicators and shows a range of colors at different pH levels, allowing the estimation of pH by comparing the resulting color change to a standard color chart. By utilizing indicators that have different color changes at various pH values, one can distinguish between acid solutions of different strengths without the need for electronic pH meters.