Question

What is the molar mass of\[{C_6}{H_6}\]?
A) \[77g/mol\]
B) \[12g/mol\]
C) \[76g/mol\]
D) \[78g/mol\]

Answer 1

Hint: We have to know that the \[{C_6}{H_6}\] is the chemical formula benzene. Benzene is a cyclic molecule or it can be also known as an aromatic compound since the carbon atoms are arranged in cyclic structure. Atomic mass is the same as molar mass just the difference arises in units.

Complete answer:
We are going to study about the molar mass first, then we will solve the question easily.
Molar mass is the weight of one sample mole, also molar mass can be defined as the mass of a given compound or element divided by the amount of substance in mol.
For Example: Atomic mass of \[Na = 22.98\~23amu\]or \[23g/mol\]
\[1mol = No.ofatomsin12gmofC - 12\] (Avogadro’s number)
i.e. In \[23gmofNa\], there is \[1{\text{ }}mol\] or \[6.022 \times {10^{23}}Na\] atoms
So we need to calculate the molar mass of \[{C_6}{H_6}\]
Molar mass of \[C = {\text{ }}12g/mol\]
Total no. of \[C\] atoms=$6$
So, \[12 \times 6 = 72g/mol\]
Molar mass of \[H = 1g/mol\]
Total no. of \[H\] atoms$ = 6$
So, \[1 \times 6 = 6g/mol\]
Therefore molar mass of \[{C_6}{H_6}\]=\[72 + 6 = 78g/mol\]
Option A) this is an incorrect option since while solving the question we don’t get \[77g/mol\].
Option B) this is an incorrect option since while solving the question we don’t get \[12g/mol\]. $12$\[g/mol\]is the molar mass of Carbon.
Option C) this is an incorrect option since while solving the question we don’t get \[76g/mol\].
Option D) this is a correct option as we have solved it above. \[78g/mol\]is the actual molar mass for\[{C_6}{H_6}\].

Note:
We have to remember that the benzene is an aromatic compound containing carbon and hydrogen atoms. It is an unsaturated compound since it contains a double bond between carbon atoms. Benzene is a simplest organic aromatic molecule having molecular formula \[{C_6}{H_6}\] .