Question

A visually challenged student, has to perform a lab test to detect the
presence of acid in a given solution. The acid-base indicator preferred by
him will be :
(a) Blue litmus
(b) Clove oil
(c) Red cabbage extract
(d) Hibiscus extract​

Answer 1

Answer:  Red cabbage extract

Explanation:

Answer 2

Answer:

Acids in which complete dissociation of hydrogen ion takes place are called strong acid. Similarly, bases in which complete dissociation of hydroxide ion takes place are called strong base.

In mineral acids, such as hydrochloric acid, sulphuric acid, nitric acid, etc. hydrogen ion dissociates completely and hence they are considered as strong acid. Since, in organic acids hydrogen ions do not dissociate completely, so they are weak acid.

Alkalis are water soluble base, thus in alkali; complete dissociation of hydroxide ions takes place and they are considered as strong base.

The complete dissociation of hydrogen ions or hydroxide ions is shown by a single arrow. The incomplete dissociation of hydrogen ions or hydroxide ions is denoted by double arrow.

Example of complete dissociation:

NaOH (aq) ⇨ Na+ + OH−

HCl ⇨ H+ + Cl−

Example of incomplete dissociation:

Mg(OH)2 ⇨ Mg+ + + OH− −

CH3COOH ⇨ CH3COO− + H+

Although acetic acid being an organic acid is a weak acid, but concentrated acetic acid is corrosive and can damage the skin if poured over it