Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate) ?

$10 \,mL$ of a solution of $NaOH$ is found to be completely neutralised by $8 \,mL$ of a given solution of $HCl$. If we take $20 \,mL$ of the same solution of $NaOH$, the amount of $HCl$ solution (the same solution as before) required to neutralise it will be ...... $mL$

Give two important uses of washing soda and baking soda.

A solution reacts with crushed egg-shells to give a gas that turns lime water milky. The solution contains

A solution turns red litmus blue, its $pH$ is likely to be

Five solutions $A,\,B,\,C,\,D$ and $E$ when tested with universal indicator showed $pH$ as $4,\,1,\,11,\,7$ and $9$, respectively. Which solution is

$(a)$ neutral ?

$(b)$ strongly alkaline ?

$(c)$ strongly acidic ?

$(d)$ weakly acidic ?

$(e)$ weakly alkaline ?

Arrange the $pH$ in increasing order of hydrogen-ion concentration.