Tag: preparation of gases

Quizzes (3) Questions (29)

Questions Related to preparation of gases

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Among the following compounds, which on heating do not produce ${N _2}$?

  1. (${NH _4}) _2 Cr _2 O _7$
  2. ${NH _4 Cl +Na NO _2}$
  3. ${NH _4 Cl+Ca O}$
  4. ${Ba(N _3) _2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(NH$ _4$)$ _2$Cr$ _2$O$ _7$ $\rightarrow$ N$ _2$ + Cr$ _2$O$ _3$ + H$ _2$O

NH$ _4$Cl + NaNO$ _2$ $\rightarrow$ N$ _2$ + H$ _2$O + NaCl

2 NH$ _4$Cl + CaO $\rightarrow$ 2 NH$ _3$ + CaCl$ _2$ + H$ _2$O

Ba(N$ _3$)$ _2$ $\xrightarrow{\text{heat}}$ Ba + 3N$ _2$

Thus, 2 NH$ _4$Cl + CaO will not produce N$ _2$.

Hence, the correct option is $\text{C}$
Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Select the correct statement. 

  1. Mixture of $NH _4Cl$ and $NaNO _2$ on heating gives $N _2$ gas
  2. $CFC$ is used as refrigerating fluid and as propellant in aerosols
  3. Phosgene is formed when $P _4$ reacts with $NaOH$
  4. Phosgene dissolves in water forming $P _2O _5$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heating a mixture of ammonium chloride (NH4Cl) and sodium nitrite (NaNO2) is a standard laboratory method for preparing pure nitrogen gas.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Nitrogen is obtained by the thermal decomposition of :

  1. $NH _4NO _2$
  2. $NH _4NO _3$
  3. $AgNO _3$
  4. $Pb(NO _3) _3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reactions are:

$NH _4NO _3\rightarrow N _2O+H _2O$

$NH _4NO _2\rightarrow N _2+H _2O$

$AgNO _3\rightarrow Ag+NO _2+1/2O _2$

So, nitrogen is obtained from $NH _4NO _2$

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Which one of the following pairs is obtained on heating ammonium dichromate?

  1. $N _2$ and $H _2$O
  2. $H _2$O and $H _2$O
  3. $NO _2$ and $H _2$O
  4. NO and $NO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
On heating ammonium dichromate; $N _2$,$H _2O$ and $Cr _2O _3$ are formed.
 
$(NH _4) _2Cr _2O _7 (s) \longrightarrow N _2 (g) + 4H _2O (g) + Cr _2O _3 (s)  \Delta H = -429 kcal/mol$

Option (A) is correct.
Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

On heating ammonium dichromate, the gas evolved is:

  1. oxygen.

  2. ammonia.

  3. nitrous oxide.

  4. nitrogen.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$ (NH _4) _2Cr _2O _7(s) \rightarrow N _2(g) + 4H _2O(g) + Cr _2O _3(s)$ 


Ammonium dichromate decomposes on heating to produce nitrogen gas water vapour (gaseous due to the temperature of the reaction), and solid chromium(III) oxide.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

$(NH _4) _2Cr _2O _7$ on heating liberates gas. The same gas will be obtained by :

  1. heating $NH _4NO _2$
  2. heating $NH _4NO _3$
  3. treating $Mg _3N _2$ with $H _2O$
  4. heating $H _2O _2$ on $NaN0 _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
On heating, $(NH _{4}) _{2}Cr _{2}O _{7}$ gives, nitrogen gas. 

$(NH _{4}) _{2}Cr _{2}O _{7}\rightarrow N _{2}+Cr _{2}O _{3}+4H _{2}O$
          (Orange)                                 (Green)

But whenever, $NH _4NO _2$ and $NH _4NO _3$ heated, then nitrogen and nitrogen dioxide gas liberated.

$NH _{4}NO _{2}\rightarrow N _{2}+2H _{2}O$

$NH _{4}NO _{3}\rightarrow N _{2}O+2H _{2}O$

So, the correct option is $A$
Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

The products formed when an aqueous solution of hydrazine reacts with an aqueous alkaline solution of potassium ferricyanide are:

  1. ${K} _{4}[Fe{(CN)} _{6}]$ and ${H} _{2}$.
  2. $4{K} _{4}[Fe{(CN)} _{6}]+4H _2O$ and ${N} _{2}$.
  3. $4{K} _{4}[Fe{(CN)} _{6}]$ and ${H} _{2}$.

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$4{K} _{3}[Fe{(CN)} _{6}]+4KOH+{N} _{2}{H} _{4}\longrightarrow 4{K} _{4}[Fe{(CN)} _{6}]+4{H} _{2}O+{N} _{2}$.

Hence, the given statement is false.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Complete the given reaction :


${(NH _4)} _2Cr _2O _7  \longrightarrow$

  1. $3N _2+ 4H _2O+ 2Cr _2O _3$
  2. $N _2+ 3H _2O+ Cr _2O _3$
  3. $N _2 + 4H _2O+ Cr _2O _3$
  4. $4N _2+ 4H _2O+ Cr _2O _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The thermal decomposition of ammonium dichromate is (NH4)2Cr2O7 -> N2 + 4H2O + Cr2O3. This is a classic volcano reaction.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Which of the following on heating will not evolve N$ _2$ gas?

  1. NH$ _{3}$ + NaNO$ _{2}$
  2. NH$ _{4}$Cl + NaNO$ _{2}$
  3. N$ _{2}$O + Cu
  4. (NH$ _{4}$)$ _{2}$Cr$ _{2}$O$ _{7}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The given reactions take place as:


$NH _3 + NaNO _2 \rightarrow NH _3NO _2 + Na$


$NH _4Cl + NaNO _2 \rightarrow N _2 + NaCl + 2H _2O$

$N _2O +Cu \rightarrow N _2 + CuO$

$(NH _4) _2Cr _2O _7 \rightarrow N _2 + Cr _2O _3 + H _2O$



Hence, the reaction between ammonia and sodium nitrate do not evolve $N _2$ gas. 

Thus option A is the correct answer.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

$Mg _3N _2 \xrightarrow{H _2O} A(gas) \xrightarrow[\triangle]{CuO} B + C(g) + H _2O$
$C(g)$ can be obtained by heating:

  1. $(NH _4) _2SO _4$
  2. $(NH _4) _2Cr _2O _7$
  3. $NH _4NO _3$
  4. $NH _4Cl$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$Mg _3N _2 \xrightarrow []{3H _2O} \underset {(A)}{2NH _3}+3MgO$

$NH _3 \xrightarrow []{CuO} \underset {(C)}{N _2}(g)+\underset {(B)}{Cu}+H _2O$
$N _2$ will be obtained by decomposition of Ammonium dichromate.
$(NH _4) _2Cr _2O _7 (s) \longrightarrow Cr _2O _3(g)+\underset {(C)}{N _2}+4H _2O$ .