STD 12 - 4. d and f- block elements — JEE STD 11 Science — Question

${A_{2\left( g \right)}} \longrightarrow {B_{\left( g \right)}} + \frac{1}{2}\,{C_{\left( g \right)}}$ the increase in pressure from $100\, mm$ to $120\, mm$ is noticed in $5\,\min$. The rate of dissappearence of $A_2$ in $mm\, min^{-1}$ is

$A$ and $B$ combine to form new substance $X$ . If $4\,moles$ of $B$ combine with $1\,mole$ of $A$ to give $1\,mole$ of $X,$ then weight of one mole of $X$ is ........... $\mathrm{g}$

$(A)\,Cu$ $(II)$ complexes are always paramagnetic

$(B)\,Cu$ $(I)$ complexes are generally colourless

$(C)\,Cu$ $( I )$ is easily oxidized

$(D)$ In Fehling solution, the active reagent has $Cu$ $( I )$