We know that balancing of a chemical equation is entirely bases on law of conservation of mass. However the concept of Principle of Atom Conservation (POAC) can also be related to law of consevation of mass in a chemical reaction. So, POAC can also act as a technique for balancing a chemical equation. For example, for a reaction:
`ABC_(3) rarr AB+C_(2)`
On applying POAC for A , B and C and related the equations , we get : `(n_(ABC_(3)))/(2) =(n_(AB))/(2) =(n_(C_(2)))/(3)`
(`n_(x)` : number of moles of X)
Thus , the cofficients of `ABC_(3)` , AB and `C_(2)` in the balanced chemical equation will be 2,2 and 3 respectively and the balanced chemical equation can be represented as ,
`2ABC_(3) rarr 2AB + 3C_(2)` Which of the following statements jis correct balanced chemical equation,
`pA+qB_(2) rarr rA_(2)B_(5)`

Options

A. 2p=r
B. q=1.25 p
C. r=2q
D. q=0.8 p

Answer

B

Explanation

On applying POAC for A & B respectively, we get
`1xxn_A=2xxn_(A_2B_6)`..(1)
`2xxn_(B_2)=5xxn_(A_2B_6)`..(2)
by (1) & (2) , `n_A/4=n_(B_2)/5=n_(A_2B_6)/2`
`:.`balanced equation : `4A+5B_2to2A_2B_6`
`:. q=1.25 p`