The answer would be D. The only minerals harder than corundum is diamond.
To know the density you also need to know the volume of the rock.
The iupac name of the compound will be hex-3-yne or 3-hexyne. By marking number of carbon in the given compound, it was found that triple bond comes at third position and there are total 6 carbon in the compound. So it will have Hex as a prefix and as it contains triple bond so it will have yne as a suffix and as the triple bond is at third position, so it will be hex-3-yne or 3-hexyne.
Chemical bonds is the answer
