Question

Observations were recorded in the table given below when a piece of graphite and a non-metal X were treated with nitric acid. Choose the option correctly depicting A, B, X and Y.​

Reactant	Product	Product	Characteristic
A piece of graphite​	Gas A​	Gas B	Gas A is a green house gas.​
Nonmetal X​	Compound Y​	Gas B​

• A. A: $C{O}_2$; B: $N{O}_3$; X: $S$; Y: $P_2{O}_5$
• B. A: $S{O}_2$; B: $N{O}_2$; X: $P$; Y: $P_2{O}_5$
• C. A: $S{O}_2$; B:$N{O}_3$; X: $S$; Y:$H_{3}P{O}_4$
• D. A: $C{O}_2$; B:$N{O}_2$; X: $P$; Y: $H_{3}P{O}_4$

Answer 1

The correct option is D A: $C{O}_2$; B:$N{O}_2$; X: $P$; Y: $H_{3}P{O}_4$

• Graphite is an allotrope of carbon, thus the nonmetal used is carbon.​
• The reaction of carbon with nitric acid: $C\left(s\right)+4HN{O}_3\left(aq\right)\to C{O}_2\left(g\right)+2H_{2}O\left(l\right)+4N{O}_2\left(g\right)$
• Greenhouse gas​ is $C{O}_2$.
• Non-metal X used in the formation of teeth and bones is phosphorous
• The reaction of phosphorous with nitric acid: $P\left(s\right)+5HN{O}_3\left(aq\right)\to H_{3}P{O}_4\left(aq\right)+H_{2}O\left(l\right)+5N{O}_2\left(g\right)$
• Compound Y with pH < 7​ is $H_{3}P{O}_4$.
• Gas B which is common in both is $N{O}_2$.
• A is $C{O}_2$; B is$N{O}_2$; X is $P$; Y is$H_{3}P{O}_4$
• The correct option is D