For per gram of reactant, the maximum quantity of `N_(2)` gas is produced in which of the following thermal decomposition reactions?
(Given: Atomic wt. Cr = 52, u, Ba = 137 u)

Options

A. `2NH_(4)NO_(3(s)) rarr 2N_(2(g)) + 4H_(2)O_((g)) + O_(2(g))`
B. `Ba(N_(3))_(2(s)) rarr Ba_((s)) + 3N_(2(g))`
C. `(NH_(4))_(2)Cr_(2)O_(7(s)) rarr N_(2(g)) + 4H_(2)O_((g)) + Cr_(2)O_(3(s))`
D. `2NH_(3(g)) rarr N_(2(g)) + 3H_(2(g))`

Answer

D

Explanation

`{:(2NH_(4)NO_(3(s)),rarr,2N_(2(g)) + 4H_(2)O_((g)),+,O_(2(g))),("Molmass",," Molmass",,),("= 80 g mol"^(-1),," = 28 g mol"^(-1),,):}`
80 g of `NH_(4)NO_(3)` gives 28 g of `N_(2) " ":.` 1g of `NH_(4)NO_(3)` will give `= (28)/(80) xx 1 = 0.35 g`
(b) `underset(underset(=221 g mol^(-1))("Molmass"))(Ba(N_(3))_(2(g))) rarr Ba_((s)) + 3N_(2(g))`
221 g of `Ba(N_(3))_(2)` gives `3 xx 28 g` of `N_(2) " ":.` 1g of `Ba(N_(3))_(2)` will give `= (3 xx 28)/(221) xx 1 = 0.38 g`
(C ) `underset(underset(=252 g mol^(-1))("Molmass"))((NH_(4))_(2)Cr_(2)O_(7(s))) rarr N_(2(g)) + 4H_(2)O_((g)) + Cr_(2)O_(3(s))`
252 g of `(NH_(4))_(2) Cr_(2)O_(7)` gives 28 g of `N_(2) " ":.` 1g of `(NH_(4))_(2)Cr_(2)O_(7)` will give `= (28)/(252) xx 1 = 0.111 g`
(D) `underset(underset(=17 g mol^(-1))("Molmass"))(2NH_(3(g))) rarr N_(2(g)) + 3H_(2(g))`
`2 xx 17 g` of `NH_(3)` will gives 28 g of `N_(2) " ":.` 1g of `NH_(3)` will give `= (28)/(2517) xx 1 = 0.823 g`