Tag: substances in common use

Questions Related to substances in common use

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 $


Correct Option: D
Explanation:

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

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. $NaCl + NaOCl + O _2$


Correct Option: C
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.

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

The commercial salt is purified by passing :

  1. $H _2S$ gas through an alkaline solution ofsalt

  2. HCI gas through a saturated solution of salt

  3. $H _2$ gas through a solution of salt

  4. $CI _2$ gas through a saturated solution of salt


Correct Option: B
Explanation:

The common table salt is prepared by passing HCI gas through a saturated solution of salt. The precipitation is due to common ion effect.

$\underset { Salt\,solution }{ NaCl }+H^++Cl^-\longrightarrow  \underset { ppt}{ NaCl } $

Hence, option B is correct.

Statement 1: One mole of NaCl contains $2$ moles of ions.
Statement 2: NaCl is a stable salt at room temperature.

  1. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  2. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct but Statement 2 is not correct.

  4. Statement 1 is not correct but Statement 2 is  correct.

  5. Both the Statement 1 and Statement 2 are not correct


Correct Option: B
Explanation:

Option (B) is correct.

Statement 1:  One mole of $NaCl$ contains 2 moles of ions i.e. a mole of chloride and a mole of sodium.Every $NaCl$ molecules has a $Na$ and a $Cl^-$ atom. So, if you have $6.022x10^{23}$ molecules, you will have that same number of $Na$ atoms and $Cl^-$ atoms, and by definition, 1 mole is $6.022x10^{23} $atoms.

Statement 2: $NaCl$ is a stable salt at room temperature.Sodium and chlorine forms a strong ionic bond, completing the octet of both atoms.They are arranged in a face centered cubic crystal structure where each $Na^+$ or $Cl^-$ ion is surrounded by 6 of the opposite ions forming an octahedron. This makes sodium chloride a stable compound.

Statement 1: Crystals of sodium chloride go into aqueous solution as ions.
Statement 2: The sodium ion has a $1+$ change and the chloride ion has a $1-$ charge and they are hydrated by the water molecules.

  1. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  2. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct but Statement 2 is not correct.

  4. Statement 1 is not correct but Statement 2 is correct.

  5. Both the Statement 1 and Statement 2 are not correct.


Correct Option: A
Explanation:

Statement 1: Crystals of sodium chloride go into aqueous solution as ions.
$\displaystyle NaCl \rightleftharpoons Na^+ (aq) + Cl^- (aq) $
Statement 2: The sodium ion has a $1+$ change and the chloride ion has a $1−$ charge and they are hydrated by the water molecules.
Each sodium ion ( or each chloride ion) is surrounded by several water molecules.
Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

The type of bonding present in a substance can be determined from experimental data.
Based on the information in the table below, which of the following substances is most likely to represent the identity of the solid?

Melting Point Density Conductivity Alone Conductivity in Aqueous Solution
$801^{\circ}C$ $2.17\ g/cc$ None Excellent
  1. Platinum, $Pt$

  2. Sodium chloride, $NaCl$

  3. Glucose, $C _{6}H _{12}O _{6}$

  4. Quartz, $SiO _{2}$


Correct Option: B

Which of the following materials conducts electricity?

  1. Crystalline potassium chloride

  2. Fused sulphur

  3. Molten sodium chloride

  4. Diamond


Correct Option: C
Explanation:

In crystalline solids, the ions are tightly bound by strong coulombic force of attraction having greater interatomic interaction and less interparticle space. $ { Na }^{ + }$ and ${ Cl }^{ - } $ ions are free to move only in molten state or aqueous solution. Hence, they show electrical conductivity in molten state.

Brine is:

  1. aqueous solution of chloride

  2. saturated solution of $NaCl$

  3. aqueous solution of $HCl$

  4. common name of bleaching powder


Correct Option: B
Explanation:

Brine is a solution of salt ( usually sodium chloride ) in water.

Molten $NaCl$ conducts electricity due to the presence of:

  1. Free molecules

  2. Free ions

  3. Free electrons

  4. Free atoms


Correct Option: B
Explanation:

Molten sodium chloride contains sodium ions and chloride ions which are free to move. 


Hence molten sodium chloride conducts electricity.

Option B is correct.

Crude common salt is hygroscopic because of impurities of:

  1. $CaSO _{4}$ and $MgSO _{4}$

  2. $CaCl _{2}$ and $MgCl _{2}$

  3. $CaBr _{2}$ and $MgBr _{2}$

  4. $Ca\left ( HCO _{3} \right ) _{2}$ and $Mg\left ( HCO _{3} \right ) _{2}$


Correct Option: B
Explanation:

Crude common salt contains impurities such as $ CaSO _{ 4 },   CaCl _{ 2 } ,   MgCl _{ 2} $. Hence it is deliquescent (hygroscopic).

Hence option B is correct.