Tag: ammonia

Questions Related to ammonia

Freshly prepared pure dilute solution of sodium in liquid ammonia :

  1. shows copper-bronze colour.

  2. occupy larger volume than that from the sum of the volumes of $Na$ and $NH _{3}(1)$.

  3. reduced the $GeH _{4}$ to $GeH _{2}^{-}$.

  4. produced sodium amide and hydrogen gas with rusty iron wire.


Correct Option: A,D
Explanation:

In dilute solutions  of $Na$ in ammonia, the solvated electrons have a deep blue colour.

In more concentrated solutions, the solution takes on a bronze/copper colour.

The solution of sodium in liquid ammonia is quite stable on its own.

You need to add a small amount of a catalyst such as ${ FeCl } _{ 3 }$ for the sodium to react with the ammonia to form sodium amide and hydrogen gas.

$2N{ a } _{ (s) }+2N{ H } _{ 3(l) }\underrightarrow { \quad FeC{ l } _{ 3 } } 2NaN{ H } _{ 2 }(N{ H } _{ 3 })+{ H } _{ 2(g) }$
conclusion : hence the option (A) and(D) is correct.

Which of the following are correct statements?

  1. $NH _3$ can be used as a refrigerant

  2. NO is heavier than $O _2$

  3. Nitrogen diffuses fastre than $O _2$

  4. $NO _2$ is a colourless gas


Correct Option: A
Explanation:

Ammonia is amongst the oldest of all there frigerants and still used widely in the refrigeration applications. It is also the only refrigerant outside the halo-carbons group, still being used to a great extent.Ammonia refrigerant is commonly known as R717 and its chemical formula is $NH _3$.

Which of the following can be classified as a molecular hydride ?

  1. $LiH$

  2. $\mathrm { NH } _ { 3 }$

  3. $\mathrm { NiHO } _ { 6 }$

  4. $\mathrm { MgH } _ { 2 }$


Correct Option: B
Explanation:
Hydride is the product when hydrogen reacts with any other elements, except the noble gases. So hydrides are compounds where one atom is hydrogen to another more electropositive element. A hydride is an anion of hydrogen $(H^-)$.
Bonding between hydrogen & other elements is always covalent. General chemical formula of a hydride is $MH _{x}$ where   $M=$ other element with hydrogen makes a binary compound. $x=$ no. of hydrogen atoms.
Covalent or Molecular hydrides
Hydrogen atoms from a covalent bond with $p-$block atoms. General chemical formula$-XH _{(8-n)}$ where $n=$no. of electrons the element has in its atomic shell.
$NH _{3}$ is $c$ molecular hydride
$3H _{2(g)}+N _{2(g)}\rightarrow 2NH _{3(g)}$
Answer is $B)\ NH _{3}$

When chlorine reacts with a gas X, an explosive inorganic compound Y is formed. Then X and Y will be :

  1. $\displaystyle X=O _{2}$ and $\displaystyle Y=NCl _{3}$

  2. $\displaystyle X=NH _{3}$ and $\displaystyle Y=NCl _{3}$

  3. $\displaystyle X=O _{2}$ and $\displaystyle Y=NH _{4}Cl$

  4. $\displaystyle X=NH _{3}$ and $\displaystyle Y=NH _{4}Cl$


Correct Option: B
Explanation:

When $NH _3$ reacts with excess of $Cl$ an explosive substance $NCl _3$ is formed.
$NH _3 + 3Cl _2 \rightarrow NCl _3 + 3HCl$
X is $NH _3$ and Y is $NCl _3$. 

Ammonia cannot be dried over regular dehydrating agent like: 

  1. $H _{2}SO _{4}$

  2. $P _{2}O _{5}$

  3. Anhydrous $CaCl _{2}$

  4. None of these


Correct Option: A
Explanation:

Ammonia cannot be dried by passing over conc. sulphuric acid because ammonia gas reacts chemically with conc. sulphuric acid to form ammonium sulphate.
2NH3 + H2SO4 (conc.) $\rightarrow$(NH4)2SO4.

Identify $(E)$ and $(F)$ in the following:
$CaCO _3\rightarrow \underset{(g)}{(A)}+\underset{(solid)}{(B)}$

$(B)+H _2O\rightarrow (C)\overset{(A)}{\rightarrow}(D)\overset{(A)excess}{\rightarrow}(E)$

$(A)+NH _3\overset{\Delta}{\rightarrow}(F)$

  1. $(E)\ Ca(HCO _3) _2;\ (F)\ NHCONH _3$

  2. $(E)\ Ca(HCO _3); \ (F)\ NH _3CONH$

  3. $(E) \ Ca(HCO _3) _2; \ (F)\ NH _2CONH _2$

  4. None of these


Correct Option: C
Explanation:

$CaCO _3\rightarrow \underset{(g)}{CO _2}+\underset{(solid)}{CaO}$
$CaO+H _2O\rightarrow (Ca(OH) _2)\overset{(CO _2)}{\rightarrow}(CaCO _3)\overset{(CO _2)excess}{\rightarrow}(Ca(HCO _3) _2)$
$(CO _2)+NH _3\overset{\Delta}{\rightarrow}(NH _2CONH _2)$
Hence option C is correct.

$NH _3+ O _2 \longrightarrow$ (B) (brown fumes)

Identify the compound B.

  1. $NO$

  2. $NO _2$

  3. $NO _3$

  4. $HNO _2$


Correct Option: B
Explanation:

Reaction:
$4NH _3+ 7O _2 \longrightarrow 4NO _2 + 6H _2O$ 

$NH _3 + I^- \longrightarrow$ (E) (violet vapours)
What is (E) ?

  1. $I _2$

  2. $I _2^{-}$

  3. $I$

  4. $I _3^{-}$


Correct Option: A
Explanation:

Reaction:
$NH _3 + I^- \longrightarrow  I _2$ (violet vapours)

Some steamy fumes of $HI$ is formed in this reaction with lots of violet vapours of $I _2$.

$NH _3 + O _2 \overset {Pt}{\rightarrow}$$A+H _2O$

Identify the compound A.

  1. $NO$

  2. $NO _2$

  3. $NO _3$

  4. $HNO _3$


Correct Option: A
Explanation:

Reaction:
$4 NH _3 + 5 O _2 \xrightarrow  {Pt}  4 NO + 6 H _2O$

$NH _3 + H _2O \longrightarrow$ (C) + (D) (both oxy acid)

  1. (C) : $HNO _2; \, \, \, \, \, $(D) : $HNO _2$

  2. (C) : $H _2NO _3 ;\, \, \, \, \, $(D) : $HNO _3$

  3. (C) : $HNO _2 ;\, \, \, \, \, $(D) : $HNO _3$

  4. None of these


Correct Option: C
Explanation:

Reaction:
$NH _3 + H _2O \rightarrow HNO _2 + HNO _3 $