Question

Volume of $C{{O}_ {2}}$ obtained at STP by the complete decomposition of 9.85gm $BaC{{O}_ {3}}$ is:
(molecular weight of $BaC{{O}_ {3}}$ =197)
(A) 2.24 litre
(B) 1.12 litre
(C) 0.85 litre
(D) 0.56 litre

Answer 1

A decomposition reaction is complete when the mass of the container and its contents no longer changes on heating. Continue the cycle until there is no further loss of mass on heating. At this point, you know that the decomposition is complete.

Complete step by step solution:
We have been given that $BaC{{O}_ {3}}$ is decomposed:
$BaC{{O}_ {3}} \to BaO+C{{O}_ {2}}$
We need to find the volume of $C{{O}_ {2}}$ obtained at STP by the complete decomposition of 9.85gm $BaC{{O}_ {3}}$,
So, for that firstly,
We have been given that $C{{O}_ {2}}$ is obtained at STP,
Standard temperature and pressure are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data.
The volume of 1 mole of $C{{O}_ {2}}$ at STP= 22.4 litre,
We have been given the molecular weight of $BaC{{O}_ {3}}$ =197,
Now, we will be finding the moles of $BaC{{O}_ {3}}$ obtained: $\dfrac {9.85}{197} =0.05mole$,
As 1 mole of $BaC{{O}_ {3}}$gives 1 mole of $C{{O}_ {2}}$,
Therefore, number of moles of $C{{O}_ {2}}$ obtained= 0.05 mole,
So, the volume of $C{{O}_ {2}}$ obtained at STP: $22.4\times 0.05=1.12litre$
So, we can say that Volume of $C{{O}_ {2}}$ obtained at STP by the complete decomposition of 9.85gm $BaC{{O}_ {3}}$ is 1.12 litre.

Therefore, we can conclude that option (A) is correct.

Note: Decomposition, the opposite of combination, occurs when a single substance breaks down into two or more different substances. This type of chemical change is evident when fruit decomposes over time.