Question

a) Mention the general formula for unsaturated alkyne compounds.
b) Which allotrope of carbon is very hard?

Answer 1

Hint: Carbon exists in three allotropic form graphite, diamond and buckminsterfullerene so these three can be seen on the basis of their structural representation by which we can say which one is harder. Alkanes, alkene and alkynes are three types of carbon chain compounds that differ by $( - C{H_2} - )unit$ or $14$ mass unit.

Complete step-by-step answer:
A) Carbon has a very important property which we call catenation, where carbon forms bonds with the other carbon by sharing of electrons. In this catenation carbon can share one electron pair, two electrons pair or three electron pair by this we also called it as in this way that carbon will make single bond, double bond and triple bond respectively. When carbon catenation happens as single bond compounds are formed they are termed as alkanes, when double bonded compounds are formed we will call them as alkene or olefins and the third is the formation of triple bonds they are called alkynes. The compounds are also classified as saturated and unsaturated where saturated means only single bond while in unsaturated compounds formation of double and triple bond comes. So, alkynes have a general formula of ${C_n}{H_{2n - 2}}$ .

B) There are three allotropes of carbon which are diamond, graphite and buckminsterfullerene you have seen two in your daily life. Graphite is the pencil nip of grey color while diamond is the precious stone which we know present in rings. The third one buckminsterfullerene is solid at room temperature. So, the hardest is diamond among all.

Note: Whenever we have to make saturated compounds of carbon we thought of its general formula ${C_n}{H_{2n + 2}}$ while the unsaturated olefins have general formula as ${C_n}{H_{2n}}$ . If we put the value of n we will get the respective molecules like methane, ethane, propane and so on these are saturated and the alkenes are ethane, propene etc.