MCQ
The lanthanide contraction is responsible for the fact that
- A$Zr$ and $Hf$ have same atomic sizes
- B$Zr$ and $Hf$ have same properties
- C$Zr$ and $Hf$ have different atomic sizes
- ✓Both $(a)$ and $(b)$
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
$(K_f $ for benzene $= 5.12 \,K\, kg\, mol^{-1})$

$2 A ( g ) \rightleftharpoons A _{2}( g )$
at $400\, K$ has $\Delta G ^{\circ}=+25.2\, kJ mol ^{-1}$.
The equilibrium constant $K _{ C }$ for this reaction is $...... \times 10^{-2}$. (Round off to the Nearest integ $\left[\right.$ Use $: R=8.3\, J mol ^{-1} K ^{-1}, \ln 10=2.3$
$\left.\log _{10} 2=0.30,1\, atm =1\, bar \right]$
$[$ antilog $(-0.3)=0.501]$