In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): The carbonate of lithium decomposes easily on heating to form lithium oxide and CO2.


Reason (R) : Lithium being very small in size polarises large carbonate ion leading to the formation of more stable Li2O and CO2 .


(i) Both A and R are correct and R is the correct explanation of A.


(ii) Both A and R are correct but R is not the correct explanation of A.


(iii) Both A and R are not correct


(iv) A is not correct but R is correct.



(i) Both A and R are correct and R is the correct explanation of A.

Explanation: Unlike other alkali metal carbonates which are stable in heat Lithium being very small in size polarises a large CO32– ion leading to the formation of more stable Li2O and CO2.


Li2CO3 Li2O + CO2


Polarisation is the distortion of electron cloud of the anion CO32- by the cation Li2+.


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