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Question: Sodium Nitrate decomposes above \( 800{}^\circ \text{ C} \) to give. (A) \( {{\text{N}}_{2}} \) ...

Sodium Nitrate decomposes above 800∘ C800{}^\circ \text{ C} to give.
(A) N2{{\text{N}}_{2}}
(B) O2{{\text{O}}_{2}}
(C) NO2\text{N}{{\text{O}}_{2}}
(D) Na2O\text{N}{{\text{a}}_{2}}\text{O}

Explanation

Solution

Sodium Nitrate is an inorganic salt of alkali metal and nitrate group having chemical formula NaNO3\text{NaN}{{\text{O}}_{3}}. Common name of sodium Nitrate is Chile ‘saltpeter’. Decomposition of any compound refers to the stability towards the heating i.e at which temperature compound breaks down into its fragments.

Complete step by step solution:
Decomposition reaction: A decomposition reaction is a reaction that breaks down a compound into its two or simpler fragments or substances.
For general reaction as
AB→A+B\text{AB}\to \text{A}+\text{B}
Most of the decomposition reaction requires light, heat, electricity (Mode of temperature)
Further here we are having the compound sodium nitrate i.e NaNO3\text{NaN}{{\text{O}}_{3}}.
When sodium nitrate heating at low temperature it converted into NaNO2\text{NaN}{{\text{O}}_{2}} by evolving O2{{\text{O}}_{2}} gas i.e
2 NaNO3→△ 2NaNo2+O2↑\text{2 NaN}{{\text{O}}_{3}}\xrightarrow {\vartriangle \text{ }}2\text{NaN}{{\text{o}}_{2}}+{{\text{O}}_{2}} \uparrow
But when sodium nitrate heated above the temperature of 800∘ C800{}^\circ \text{ C} it decomposes into Na2O\text{N}{{\text{a}}_{2}}\text{O} N2{{\text{N}}_{2}} and by evolving of oxygen gas
2 NaNo3→800∘ C Na2 O (s)+ N2(g)(↑)+ 52 O2(g)↑2\text{ NaN}{{\text{o}}_{3}} \xrightarrow {800{}^\circ \text{ C}}\text{ N}{{\text{a}}_{2}}\text{ O }(s)+\text{ }{{\text{N}}_{2}}(g) \left( \uparrow \right)+\text{ }\dfrac{5}{2}\text{ }{{\text{O}}_{2}}(g) \uparrow
Hence, A, B and D are correct options for this question.
Means sodium nitrate when heated above 800∘ C800{}^\circ \text{ C} is breaks down into Na2O, N2\text{N}{{\text{a}}_{2}}\text{O, }{{\text{N}}_{2}} and O2{{\text{O}}_{2}} .

Note:
We know that sodium nitrate is an inorganic compound of sodium, nitrogen and oxygen. It is prepared by various methods.
Some of them as follow:
It is prepared by reaction NaOH and HNO3\text{HN}{{\text{O}}_{3}}
NaOH+HNO3→NaNo3+H2O\text{NaOH}+\text{HN}{{\text{O}}_{3}}\to \text{NaN}{{\text{o}}_{3}}+{{\text{H}}_{2}}\text{O} (Highly exothermic reaction)
It is also prepared by ammonium nitrate and sodium hydroxide.
NH4NO3+NaOH→NH4OH+NaNO3\text{N}{{\text{H}}_{4}}\text{N}{{\text{O}}_{3}}+\text{NaOH}\to \text{N}{{\text{H}}_{4}}\text{OH}+\text{NaN}{{\text{O}}_{3}}
It is also prepared on a large scale by sodium bicarbonate and nitric acid.
NaHCO3+HNO3→ NaNO3+H2O+CO2\text{NaHC}{{\text{O}}_{3}}+\text{HN}{{\text{O}}_{3}}\to \text{ NaN}{{\text{O}}_{3}}+{{\text{H}}_{2}}\text{O}+\text{C}{{\text{O}}_{2}}.