JEE MAIN - Chemistry (2005 - No. 9)
Hydrogen ion concentration in mol / L in a solution of pH = 5.4 will be :
3.98 $$\times$$ 10-6
3.68 $$\times$$ 10-6
3.88 $$\times$$ 106
3.98 $$\times$$ 108
Explicação
$$pH = - \log \left[ {{H^ + }} \right] = \log {1 \over {\left[ {{H^ + }} \right]}};$$
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,5.4 = \log {1 \over {\left[ {{H^ + }} \right]}}$$
On solving, $$\left[ {{H^ + }} \right] = 3.98 \times {10^{ - 6}}$$
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,5.4 = \log {1 \over {\left[ {{H^ + }} \right]}}$$
On solving, $$\left[ {{H^ + }} \right] = 3.98 \times {10^{ - 6}}$$