Liquids A and B form an ideal solution in the entire composition range. At 350 K, the vaapor pressures of pure A and pure B are 7 $$ \times $$ 10³ Pa and 12 $$ \times $$ 10³ Pa, respectively . The composition of the vapor in equilibriumwith a solution containing 40 mole percent of A at this temperature is :

The effect of lanthanoid contraction in the lanthanoid series of elements by and large means :

Two pi and half sigma bonds are present in :

Wilkinson catalyst is : (Et = C₂H₅)