_ _ _ _ _ the substances which are bitter to taste and soapy to touch. They turn red litmus solution blue. They give "OH" ions in aqueous solution.

EG. of ACID

_ _ _ _ _ the substance which change their colour/smell in different types of substances.

NATURAL INDICATOR

SYNTHETIC INDICATOR

Pop test: When a burning candle is brought near a test tube containing hydro gas it put off with a 'Pop' sound. This test is conducted for examining the _ _ _ _ _ .

While diluting acids, it is recommended that the acid should be added to water and not water to acid because the process of dissolving an acid or a base in water is _ _ _ _ _.

Mixing an acid or a base with H₂O results in _ _ _ _ _

Mixing an acid or a base with H₂O results in decrease of concentration of ions. Such a process is called as _ _ _ _ _.

pH Scale: A scale for measuring _ _ _ _ _ ion concentration in a solution.

P in pH stands for _ _ _ _ _ a German word which means power.

pH less than 7

pH =7

pH greater than 7

When pH of rain water is less than _ _ _ _ _ it is called acid rain

Acids react with metals gives _ _ _ _ _

Zn + H₂SO₄ =