When the crystals of green vitriol are taken in a dry test tube and strongly heated, what are noticeable changes that take place? Write a balanced chemical reaction to explain what happens.

Open in App

Solution

When green vitriol $(F e S o_{4} . 7 H_{2} O)$ is strongly heated then a mixture of two gases is formed.
$\underset{(G r e e n v i t r i o l)}{\underset{⏟}{F e S O_{4} . 7 H_{2} O (s)}} \to_{- 7 H_{2} O}^{300^{\circ} C} \underset{(F e r r o u s s u l p h a t e)}{\underset{⏟}{F e S O_{4} (s)}} \underset{(F e r r o u s s u l p h a t e)}{\underset{⏟}{2 F e S O_{4} (s)}} \to_{T e m p e r a t u r e}^{H i g h} \underset{(F e r r i c o x i d e)}{\underset{⏟}{F e_{2} O_{3} (s)}} + \underset{(S u l p h u r d i o x i d e)}{\underset{⏟}{S O_{2} (g)}} + \underset{(S u l p h u r t r i o x i d e)}{\underset{⏟}{S O_{3} (g)}}$
So in the first reaction when Ferrous sulphate heptahydrate (green vitriol) $(F e S o_{4} . 7 H_{2} O)$ is heated Ferrous sulphate $(F e S O_{4} (s))$ is formed, and then when it is more heated at higher temperatures Sulphur dioxide and Sulphur trioxide $S O_{2} (g) and S O_{3} (g)$ respectively are formed.
Now these two gases obtained are called acid anhydrides.
They form acids when mixed with water,
$\underset{(S u l p h u r d i o x i d e)}{\underset{⏟}{S O_{2} (g)}} + \underset{(W a t e r)}{\underset{⏟}{H_{2} O (l)}} \to \underset{(S u l p h u r o u s a c i d)}{\underset{⏟}{H_{2} S O_{3} (a q)}} \underset{(S u l p h u r t r i o x i d e)}{\underset{⏟}{S O_{3} (g)}} + \underset{(W a t e r)}{\underset{⏟}{H_{2} O (l)}} \to \underset{(S u l p h u r i c a c i d)}{\underset{⏟}{H_{2} S O_{4} (a q)}}$

Suggest Corrections

Similar questions

(a) What happens when copper sulphate crystals are heated strongly? Explain with help of an equation.

(b) What happens when a few drops of water are added to anhydrous copper sulphate? Explain with the help of an equation.

State your observations when following salts are heated strongly in dry state. Write chemical equations in support of your answer.

Iodine crystals $(I_{2})$

What happens when Lead nitrate is heated in a dry test tube? (write balance chemical equation)

Join BYJU'S Learning Program