Given below are two statements :

Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.

Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.

In the light of the above statements, choose the most appropriate answer from the options given below.

Which of the following ore is concentrated using group 1 cyanide salt ?

In the following reaction the reason why meta-nitro product also formed is :

What is the major product formed by HI on reaction with