What is the colour of $FeSO_{4} \cdot 7H_{2}O$ crystals? How does this colour change upon heating? Give the balanced chemical equation for the change.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) $FeSO_{4} \cdot 7H_{2}O$ crystals are green in colour. Upon heating,they first lose their water of crystallisation and turn white (anhydrous $FeSO_{4}$). On further heating,they decompose to form ferric oxide $(Fe_{2}O_{3})$,which is reddish-brown in colour,along with sulphur dioxide $(SO_{2})$ and sulphur trioxide $(SO_{3})$ gases.
Step $1$: Loss of water of crystallisation:
$FeSO_{4} \cdot 7H_{2}O(s) \xrightarrow{\Delta} FeSO_{4}(s) + 7H_{2}O(g)$
(Green) (White)
Step $2$: Decomposition of anhydrous ferrous sulphate:
$2FeSO_{4}(s) \xrightarrow{\Delta} Fe_{2}O_{3}(s) + SO_{2}(g) + SO_{3}(g)$
(Reddish-brown)

Explore More

Similar Questions

What happens when zinc granules are treated with dilute solutions of $H_{2}SO_{4}$,$HCl$,and $HNO_{3}$? Also,write the chemical equations if a reaction occurs.

Give reasons for the following:
$(i)$ All decomposition reactions are endothermic reactions.
$(ii)$ Colour of copper sulphate solution changes when an iron nail is dipped in it.
$(iii)$ Respiration is an exothermic reaction.

Study the reactions given below. State which of the following chemical reactions will take place or not,giving suitable reason for each:
$(a)$ $Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s)$
$(b)$ $Fe(s) + ZnSO_4(aq) \rightarrow FeSO_4(aq) + Zn(s)$
$(c)$ $Zn(s) + FeSO_4(aq) \rightarrow ZnSO_4(aq) + Fe(s)$

Write two observations for the following chemical reaction:
$(a)$ Potassium iodide solution is added to lead nitrate solution.

When a green iron salt is heated strongly, its colour finally changes to black and the odour of burning sulphur is given out.
$(a)$ Name the iron salt.
$(b)$ Name the type of reaction that takes place during the heating of iron salt.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo