Why Cu does not dissolve in Hcl but in Nitric acid it is oxidised ?

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Solution

Cu²⁺ ions get reduced more easily than H⁺ ions, therefore, hydrogen ions cannot oxidise Cu. Thus, Cu does not dissolve in HCl. In nitric acid it is oxidised by nitrate ion and not by hydrogen ion, so it dissolves in nitric acid.

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Similar questions

Q. Assertion :Copper dissolves in dilute nitric acid but not in dilute

H C l

Reason: Copper has positive

E^{\circ}

C u O

reacts with

H C l

but

C u

does not, why?

Explain the reason why:
(i) HCl gas fumes in moist air.
(ii) Dilute HCl cannot be concentrated beyond 22.2% by distillation.
(iii) Dilute acids are stronger electrolytes as compared to concentrated acid.
(iv) Liquid ammonia has no action on litmus while liquor ammonia has an effect.
(v) Ammonia is not collected over water.
(vi) Pure nitric acid does not dissolve gold or platinum, but aqua regia dissolves them.

Q. Give reasons for the following:
(i) In laboratory preparation of nitric acid all the apparatus including cork should be made up of glass.
(ii) Commercial nitric acid is yellow in colour, but when it is diluted with water, it turns colourless.
(iii) Aluminium does not react with nitric acid of any concentration.
(iv) Conc. nitric acid renders iron passive.
(v) Nitric acid is used in purification of gold.
(vi) Aqua regia dissolves gold and platinum.
(vii) Nitric acid usually does not yield hydrogen from acids.
(viii) Lightning is a blessing in disguise.
(ix) Concentrated nitric acid is brown in colour.
(x) Concentrated nitric acid is a stronger oxidizing agent.

Q. Copper dissolves in

H N O_{3}

, but not in

H C l

. Why?

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Why Cu does not dissolve in Hcl but in Nitric acid it is oxidised ?

Cu2+ ions get reduced more easily than H+ ions, therefore, hydrogen ions cannot oxidise Cu. Thus, Cu does not dissolve in HCl. In nitric acid it is oxidised by nitrate ion and not by hydrogen ion, so it dissolves in nitric acid.

Cu²⁺ ions get reduced more easily than H⁺ ions, therefore, hydrogen ions cannot oxidise Cu. Thus, Cu does not dissolve in HCl. In nitric acid it is oxidised by nitrate ion and not by hydrogen ion, so it dissolves in nitric acid.