Question

$C{l^ - }$ is confirmed by chromyl chloride test.
If the given statement is true enter $1$ else enter $0$ .

Answer 1

Hint : The chromyl chloride test is performed to detect chloride ions in the qualitative analysis. When any chloride salt for example sodium chloride $(NaCl)$ is heated with acidified potassium dichromate it gives fumes of chromyl chloride which used to be in orange -red colour. This confirms the presence of chloride ions in the salt.

Complete answer:
- Lets learn about chromyl chloride tests in detail. When the chloride salt is added with potassium dichromate $({K_2}C{r_2}{O_7})$ in dilute sulphuric acid then dark red vapours of chromyl chloride are formed. When fumes of chromyl chloride is passed through sodium hydroxide $(NaOH)$ solution .The resultant solution becomes yellow . Then add a small amount of acetic acid and then lead acetate to the solution then we will get yellow precipitate at the end which indicates the presence of $C{l^ - }$.
${K_2}C{r_2}{O_7} + 4NaCl + 6{H_2}S{O_4} \to {K_2}S{O_4} + 2N{a_2}S{O_4} + 2Cr{O_2}C{l_2} + 3{H_2}O$
- Now the vapours are passed to sodium hydroxide solution to form $N{a_2}Cr{O_4}$.
$2NaOH + Cr{O_2}C{l_2} \to N{a_2}Cr{O_4} + 2HCl$
- Here in the above reaction $Cr{O_2}C{l_2}$ is orange -red vapours of chromyl chloride. So the given statement is true then we will enter $1$ . The chloride salt of silver, mercury, antimony and lead are covalent in nature so these salt do not generate chloride ions and they do not give chromyl chloride test as well .Ionic chlorides give chromyl chloride test.

Note : The chromyl chloride test is a specific test to check the presence of chloride ions in the salt. The presence of chloride ion is determined when we get red, orange fumes of chromyl chloride. No such fumes will be produced during the test if there is no chloride ion in the salt.