Which of the statements is not true ?
A. On passing `H_(2)S` through acidified `K_(2)Cr_(2)O_(7)` solution , a milky colour is observed
B. `Na_(2)Cr_(2)O_(7)` is preferred over `K_(2)Cr_(2)O_(7)` in volumetric analysis
C. `K_(2)Cr_(2)O_(7)` solution in acidic medium is orange
D. `K_(2)Cr_(2)O_(7)` solution becomes yellow on increasing the pH beyond 7
