Boron halides behave as Lewis acids because of their nature.

The collector plate in an experiment on the photoelectric effect is kept vertically above the emitter plate. $A$ light source is turned on and a saturation photocurrent is recorded. An electric field is then switched on which has a vertically downward direction.

These are regarded as major causes of biodiversity loss :
$A.$ Over-exploitation
$B.$ Co-extinction
$C.$ Mutation
$D.$ Habitat loss and fragmentation
$E.$ Migration
Choose the correct option :

Which one of the following is true for an exothermic reaction $A \rightleftharpoons B$,if $E_f$ and $E_b$ are the activation energies of forward and backward reactions respectively?

Which one of the following is used in the preparation of styrene?

An inverted bell lying at the bottom of a lake $47.6 \, m$ deep has $50 \, cm^3$ of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be ......... $cm^3$ (atmospheric pressure $= 70 \, cm$ of $Hg$ and density of $Hg = 13.6 \, g/cm^3$).