Which from following molecules exhibits highest acidic nature?

What is the number of moles of $$\mathrm{sp}^2$$ hybrid carbon atoms in one mole of hexa-1,4-diyne?

Which of the following is NOT obtained when a mixture of methyl chloride and n-propyl chloride is treated with sodium metal in dry ether?

Which carbon atoms (numbered from $$C_1$$ to $$C_6$$ ) are involved in the formation of ring structure of glucose?