(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.
(b) Water; acids produce hydrogen(H+) ions in water which determines their acidic nature.
(c) Hydrogen ions; concentration of hydrogen ions determines the strength of acids.
(d) Olfactory; examples- onion and vanilla.
(e) Olfactory; indicates by odour change.