Question

When a current is passed through a solution of salt water, sodium chloride decomposes according to the following reaction:

2NaCl + 2H2O → 2NaOH + Cl2 + H2.

Using the periodic table, what are the molecular masses of the starting and ending substances?

NaCl = g/mole
A 58.44
B 35.45
C 22.9

Cl2 = g/mole
A 35.45
B 70.90

Answer 1

For NaCl: The correct answer is Option A.

For
`Cl_2` : The correct answer is Option B.

Step-by-step explanation:

Molar mass is defined as the sum of the mass of all the atoms each multiplied its atomic masses that are present in the molecular formula of a compound. It is expressed in g/mol.

For the given chemical reaction:

`2NaCl+2H_2O\rightarrow 2NaOH+Cl_2+H_2`

The reactants are
`NaCl\text{ and }H_2O`

The products are
`NaOH,Cl_2\text{ and }H_2`

We know that:

Molar mass of Sodium = 22.99 g/mol

Molar mass of Chlorine = 35.45 g/mol

For starting substance NaCl:

Molar mass of NaCl =
`[(1* 22.99)+(1* 35.45)]=58.44g/mol`

Hence, the correct answer is Option A.

For starting substance
`Cl_2` :

Molar mass of
`Cl_2=(2* 35.45)=70.90g/mol`

Hence, the correct answer is Option B.

Answer 2

The answers are the following:
1.B 35.45
2.B 70.90