Tag: salts and their properties

Quizzes (0) Questions (39)

Questions Related to salts and their properties

Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

The product of electrolysis of conc. solution of common salt is?

  1. $Na+Cl _{2}$
  2. $H _{2}+O _{2}$
  3. $NaOH+H _{2}+Cl _{2}$
  4. $Na+Cl _{2}+O _{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ionization of salt:

$NaCl\rightarrow Na^{+}+Cl^{-}$

The half-reaction at the cathode is:

$H _2O+2e^{−}\rightarrow H _2+2OH^{−}$

Here, the reduction is taking place.

The half-reaction at the anode is:

$2Cl^{-}\rightarrow Cl _2+1e^{−}$

Here, oxidation is taking place.

The overall reaction is as follows:

$NaCl+H _2O\rightarrow Na^{+}+OH^{−}+H _2+Cl _2$.

Hence, option $C$ is correct.
Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

Which impurity (as a salt) is associated with table salt obtained from sea-water?

  1. $NaHCO _3$
  2. $MgCO _3$
  3. $MgCl _2$
  4. $NaI$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sea water contains $MgCl _2$ brine so salt made from sea water contains this as impurity.
sea salt:

 Chloride $(Cl^-)$  55.03%
 Sodium $(Na^+)$  30.59%
 Sulfate $(SO _4^{2-}$ 7.68% 
 Magnesium $(Mg^{2+})$ 3.68% 
 Calcium $(Ca^{2+})$ 1.18% 
 Potassium $(K^+)$ 1.11% 
 Bicarbonate $(HCO _3^-)$ 0.41% 
 Bromide $(Br^-)$ 0.19% 
Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

The metal whose hydroxide does not decompose on heating but its nitrate decomposes is:

  1. $Ca$
  2. $Al$
  3. $Na$
  4. $Fe$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$NaOH \xrightarrow {heat} $ no reaction
$NaNO _3 \xrightarrow {heat} NaNO _2+\frac{1}{2}O _2$

The metal whose hydroxide does not decompose on heating but its nitrate decomposes is sodium.

Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

Sodium chloride imparts a yellow color to the Bunsen flame. This can be interpreted due to the :

  1. low ionisation of energy of sodium

  2. sublimation of metalic sodium to give yellow vapour

  3. emission of excess energy absorbed as a radiation in the visible region

  4. photo sensitivity of sodium
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Sodium chloride imparts a yellow color to the Bunsen flame. This can be interpreted due to the emission of excess energy absorbed as a radiation in the visible region.
When an alkali or akaline earth metal (or its salt) is introduced in the flame, the valence electrons of the metal absorbs energy and are excited to the higher energy level. When excited electrons return to their ground state, they release the absorbed energy as visible light.
Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

Commercial common salts become slightly damp on keeping. This is due to the fact that:

  1. common salt is hygroscopic

  2. common salt contains some impurities which are hygroscopic

  3. common salt is efflorescent

  4. common salt is crystalline
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Commercial common salt commonly becomes slightly damp on keeping because common salt contains some impurities like ${MgCl _2}$ and ${CaCl _2}$ which are hygroscopic in nature and absorb moisture from the atmosphere.
Hence, option B is correct.

Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

Which one of the following products is formed when a mixture of steam, sulphur dioxide gas and oxygen gas (from air) is passed over dry lumps of common salt, the sodium chloride?

  1. $ Na _2SO _3 $
  2. $ Cl _3 $
  3. $ NaHSO _3 $
  4. $ Na _2SO _4 $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hargreaves process:
$ 4NaCl (s) + 2SO _2 (g) + 2H _2O (g) + O _2 (g) \longrightarrow 2Na _2SO _4 + 4HCl $

Multiple choice chemistry substances in common use salts and their properties study of some important salts salts used in daily life

Reaction, $Cl _2 + 2NaOH \rightarrow P$            

What are the products?

  1. $NaCl + NaOCl + H _2$
  2. $NaCl + NaOCl + H _2O _2$
  3. $NaCl + NaOCl + H _2O$
  4. $NaCl + NaOCl + O _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The reaction of non-metals with bases is complex. Example: When chlorine reacts with a base like sodium hydroxide, it gives multiple products like sodium hypochlorite, sodium chloride and water.

$Cl _2 + 2NaOH \rightarrow NaCl + NaOCl + H _2O$