Test: Carbon and its compounds (Easy) - Class 10 MCQ

Rule-I Selection of the longest carbon chain.

Rule-ll Numbering the longest chain: Longest chain is numbered starting from a terminal carbon. Numbering is done in such a way that the lowest possible number is given to the sidechain or a functional group.

Rule-Ill Writing names of branched, saturated hydrocarbons, locants are written first in alphabetical order followed by the name of the parent chain.

Rule-IV Some common names are retained in IUP AC system for unsubstituted hydrocarbons only. Stability order: D > C > B > A

Electron withdrawing groups destabilize carbocation. Here, Cl is an electron-withdrawing group hence, it destabilizes the carbonation. But as the distance increases between carbocation and electron-withdrawing groups which can be seen in A, B, and C molecules. Hence, an order is C > B > A and in the case of (D) molecules, there is no electron-withdrawing group. Hence, it's more stable as compared to others.

Graphite differs from diamond because graphite is slippery to touch and a good conductor of electricity. In graphite, free electrons move throughout the entire layers, and hence graphite is a good conductor of electricity. Whereas in diamond, there are no mobile electrons in the system. Hence, diamond crystals are non-conductor of electricity. Diamond is a hard beautiful crystalline substance.

In an organic compound having multiples bonds the order of preference is given as,

Triple bond>Double bond>Single bond So,

We should number the carbon from the right. As it can be seen from the figure the correct order of numbering and nomenclature is right one. The left part violated the IUPAC rule stated above and hence the correct IUPAC name of the compound will be pent-3-en-1-yne.

Priority of -OH group is greater than halide group. Numbering will be started from the right en(d) IUPAC name: 4-chloro-3-methylbut-2-en-1-ol.