Chemical reactions involve interation of atoms and molecules. A large number of atoms `//` molecules `(` approximately `6.023xx10^(23))` are present in a few grams of any chemical compound varying with their atomic `//` molecular masses. To handle such large numbers conveniently, the mole concept was introduced. This concept has implications in diverse areas such as analytical chemistry, biochemistry, electrochemistry, and radiochemistry. The following example illustrates a typical case, involving chemical `//` electrochemical reaction, which requires a clear understanding of the mole concept.
A `4.0M` aqueous solution of `NaCl` is prepared and `500mL` of this solution is electrolyzed. This leads to the evolution of chlorine gas at one of the electrodes `(` atomic mass of `Na ` is 23 and `Hg` is `200)(1F=96500C)`.
The total number of moles of chlorine gas evolved is

Options

A. 0.5
B. `1.0`
C. `2.0`
D. `3.0`

Answer

B

Explanation

500 ml of 4.0 molar NaCl solution contains 2 mole of NaCL. The chlorine content of this sample will evolve as chlorine gas. The number of mole of NaCl=numer mole of `Cl^(-)=2`mole
`therefore`Number of mole of `Cl_(2)` gas evolved`=(2)/(2)=1` mole.