Question

A shiny brown coloured element ${}^{\prime }{X}^{\prime }$ on heating in air forms a black coloured substance ${}^{\prime }{Y}^{\prime }$. If a gas ${}^{\prime }{Z}^{\prime }$ is passed through the substance ${}^{\prime }{Y}^{\prime }$, the black colour turns brown as the reverse reaction takes place and ${}^{\prime }{X}^{\prime }$ is obtained. ${}^{\prime }{Z}^{\prime }$ is a highly combustible diatomic gas. The symbols formulae of ${}^{\prime }{X}^{\prime }{,}^{\prime }{Y}^{\prime }$ and ${}^{\prime }{Z}^{\prime }$ respectively are

• A. $Cu,C{u}_{2}O,H_2$
• B. $Cu,CuO,O_2$
• C. $Cu,C{u}_{2}O,O_2$
• D. $Cu,CuO,H_2$

Answer 1

The correct option is D $Cu,CuO,H_2$

Answer (1)
Shiny brown coloured element ${}^{\prime }{X}^{\prime }$ is copper $\left(Cu\right)$