AIPMT 2011 Preliminary Mock Test

Which of the following compounds has the lowest melting point?

Which of the following pairs of metals is purified by van Arkel method?

The correct order of increasing bond length of $\text{C}-\text{H}$, $\text{C}-\text{O}$, $\text{C}-\text{C}$ and $\text{C}=\text{C}$ is:

Acidified ${\text{K}}_2{\text{Cr}}_2{\text{O}}_7$ solution turns green when ${\text{Na}}_2{\text{SO}}_3$ is added to it. This is due to the formation of:

For the four successive transition elements ($\text{Cr, Mn, Fe}$ and $\text{Co}$), the stability of $+2$ oxidation state will be there in which of the following order? (At. nos. $\text{Cr}=24,\text{Mn}=25,\text{Fe}=26,\text{Co}=27$)