Question

Metals which do not react with dilute acids:
$$\begin{array}{l}A:Cu\\ B:Ag\\ C:Hg\\ D:Allofthese\end{array}$$

Answer 1

Hint:Dilute acids comprise a large quantity of water. Concentrated acids are diluted by adding water. Acid is actually referred to as a substance that expels hydrogen ions (i.e. $$H^{+}$$) when it gets dissolved in water.

Complete step by step answer:
Dilute acids generally react with reactive metals like magnesium, zinc, aluminium and iron. The reaction results in the formation of a salt and hydrogen gas. Name of the salt depends upon the name of acid. An easy way to remember is the term ‘MASH’ i.e.
($$M+A\to S+H$$).
$$metal+acid\to salt+hydrogen$$
For instance, Magnesium or zinc reacts with hydrochloric acid and sulphuric acid, respectively to form their respective salts and hydrogen gas. The reactions are depicted below:
$$\begin{array}{l}Mg+2HCl\to MgC{l}_2+H_2\\ Zn+H_{2}S{O}_4\to ZnS{O}_4+H_2\end{array}$$
The rate of reaction is directly proportional to the reactivity of metal i.e. more reactive the metal is, faster will be the reaction. In the question, we are given basically three metals i.e. copper, silver and mercury. If you look at the reactivity series of metals, these all three given elements are very less reactive as they do not get oxidized (or we can say donate electrons) easily. As a result, copper, silver and mercury cannot react with the dilute acid as they won’t displace the hydrogen from non-metal anion.

Hence, Option D is correct.

Note: The most reactive element in a reactivity series is positioned at the top while the least reactive element is positioned at the bottom. Higher reactive metals tend to lose electrons easily and form the positive ions.