Complete and balance the following chemical equations:

(a) dilutesulphuric acid reacts with zinc granules.

(b) dilute hydrochloric acid reacts with magnesium ribbon.

(c) dilutesulphuric acid reacts with aluminium powder.

(d) dilute hydrochloric acid reacts with iron fillings.

(a) Acid have a --------tasks and they turn -------litmus to --------

(b) Substance do not show their acidic properties without ----------

(c) Acids produce ------- ions on dissolving in water.

(d) Those substance whose smell (or odour) changes in acidic or basic solutions are called ------indicators.

(e) Onion and vanilla extract are ------ indicators.