Copper when exposed to moist air having CO2. It gets superficially coated with a green layer of basic carbonate CuCO3. Cu (OH)2.
Copper becomes green when exposed to moist air for a long period. This is due to:
Held on 12 Apr 2014 · Verified 6 Jul 2026.
the formation of a layer of cupric oxide on the surface of copper.
the formation of a layer of basic carbonate of copper on the surface of copper.
the formation of a layer of cupric hydroxide on the surface of copper.
the formation of basic copper sulphate layer on the surface of the metal.
Sign in to track your attempts and accuracy.
Sign in to keep a private note on this question. Nothing you write is ever public.
First and second ionization enthalpies of lithium are $520$ kJ mol$^{-1}$ and $7297$ kJ mol$^{-1}$ respectively. Energy required to convert $3.5$ mg lithium (g) into $\text{Li}^{2+}$(g) $[\text{Li(g)} \rightarrow \text{Li}^{2+}\text{(g)}]$ is _______ kJ mol$^{-1}$. (nearest integer) [Molar mass of Li $= 7$ g mol$^{-1}$]
Regarding the hydrides of group 15 elements $\mathrm{EH}_{3}(\mathrm{E}=\mathrm{N}, \mathrm{P}, \mathrm{As}, \mathrm{Sb})$, select the correct statement from the following: A. The stability of hydrides decreases down the group. B. The basicity of hydrides decreases down the group. C. The reducing character increases down the group. D. The boiling point increases down the group. Choose the correct answer from the options given below:
Which of the following elements has the highest electronegativity?
Which of the following elements has the highest electronegativity?
In a period, the first ionisation enthalpy of the element at extreme left and the negative electron gain enthalpy of the extreme right element, except noble gases, are respectively.
Work through every JEE Main Inorganic Chemistry PYQ, year by year.