Which of the statements is not true?

Options

1. AOn passing $\mathrm{H}_2 \mathrm{~S}$ through acidified $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution, a milky colour is observed
2. B$\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ is preferred over $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ in volumetric analysis
3. C$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution in acidic medium is orange
4. D$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution becomes yellow on increasing the $\mathrm{pH}$ beyond 7