Question

The total positive charge in a glass of water containing 180 gm of water is approximately :

• A. $1.0\times 10^7$ coulomb
• B. $6.03\times 10^7$ coulomb
• C. $1.80\times 10^7$ coulomb
• D. $1.20\times 10^7$ coulomb

Answer 1

Answer: (A)

The number of molecules in 18 g of water $=6.02\times 10^{23}$
$\therefore$ Number of molecules in 180 g of water
$=6.02\times 10^{23}\times \frac{180}{18}=6.02\times 10^{24}$
The number of protons in a molecule of water = 10
So, total number of protons,
$n=6.02\times 10^{24}\times 10=6.02\times 10^{25}$
The total charge, q = ne
$=6.02\times 10^{25}\times 1.6\times 10^{-19}=0.96\times 10^7$
$\approx 1.0\times 10^{7}C$.