Ans 1 We can test alcohol by lucas reagent .
Ans 2 When ethyne is burnt in air, it gives a sooty flame. This is due
to incomplete combustion caused by limited supply of air. However, if ethyne is
burnt with oxygen, it gives a clean flame with temperature 3000°C because of
complete combustion. This oxy-acetylene flame is used for welding. It is not
possible to attain such a high temperature without mixing oxygen. This is the
reason why a mixture of ethyne and air is not used.
Ans 3 Boron : 1s2 2s2 2p1