Litmus test (politics) Litmus test (politics) A litmus test is a question asked of a potential candidate for high office, the answer to which would determine whether the nominating official would proceed with the appointment or nomination. The expression is a metaphor based on the litmus test in chemistry, in which one is able to test the general acidity of a substance, but not its exact pH. Those who must approve a nominee, such as a justice of the Supreme Court of the United States, may also be said to apply a litmus test to determine whether the nominee will receive their vote.
Soil of the acidity or alkalinity of the soil. More precisely, it is a measure of hydrogen ion concentration in an aqueous solution and ranges in values from 0 to 14 (acidic to basic) but practically speaking for soils, pH ranges from 3.5 to 9.5, as pH values beyond those extremes are toxic to life forms. At 25 °C an aqueous solution that has a pH of 3.5 has 10 moles H (hydrogen ions) per litre of solution (and also 10 mole/litre OH). A pH of 7, defined as neutral, has 10 moles hydrogen ions per litre of solution and also