The hydronium ion concentration in pure water is $1 \times 10^{-7}$ mol$L^{-1}$. The degree of dissociation of water is

Question

(a) $1.8 \times 10^{-9}$

(b) $0.8 \times 10^{-8}$

(c) $9.8 \times 10^{-6}$

(d) $3 \times 10^{-9}$