Tag: chemical equilibrium and acids-bases

Questions Related to chemical equilibrium and acids-bases

All  salts  are:

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. strong electrolytes

  2. weak electrolytes

  3. non electrolytes

  4. either weak or strong electrolyte

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Correct Option: A
Explanation:
As, substances that give ions when dissolved in water are called $electrolytes$.They can be divided into acids, bases and salts, because they all give ions when dissolve in water. 
$Strong$ $electrolytes$ completely ionize when dissolve in water, and no neutral molecules are formed in solution.
Example - $NaCl$, $HNO _{3}$ etc.

As we know, chemically, a salt is an ionic compound as it is composed of two oppositely charged ions - cation and anion. Due to the presence of ions, they are good conductors of heat and electricity in a molten state and in solutions.
So, all salts are strong electrolytes as they completely dissolve in water and dissociates into their component ions.

Hence, option $A$ is correct.

The loss of water of crystallization to the atmosphere by a compound is termed:

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. deliquescence

  2. dehydration

  3. efflorescence

  4. hydrolysis

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Correct Option: C
Explanation:

Efflorescence, spontaneous loss of water by a hydrated salt,  which occurs when the aqueous vapor pressure of the hydrate is greater than the partial pressure of the water vapour in the air. 

An aqueous solution of a salt of a weak base and a strong acid is acidic, because of:

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. electrolysis

  2. hydrolysis

  3. dissociation

  4. none of these

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Correct Option: B
Explanation:

In neutralization reaction weak base reacts with strong acid to give salt of strong acidic solution and water.

${ NH } _{ 4 }OH+{ H } _{ 2 }{ SO } _{ 4 }\rightarrow \left( { NH } _{ 4 } \right) _{ 2 }{ SO } _{ 4 }+{ H } _{ 2 }O$

Aqueous solution of which of the following salts turns the red litmus blue?

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. $Na _2CO _3$

  2. $NaHCO _3$

  3. $Na _2CO _3\cdot 10H _2O$

  4. All of these

Show answer
Correct Option: D
Explanation:

Sodium carbonate and sodium bicarbonate are basic salts which turn red litmus blue as they are alkaline in nature having pH more than 7.

A salt is a general name given to the chemical produced during _______ reaction between an acid and a base

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. decomposition

  2. neutralization

  3. displacement

  4. double decomposition

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Correct Option: B
Explanation:

A salt is a general name given to the chemical produced during the neutralization reaction between an acid and a base.

Sea water contains about 24g of salts dissolved per litre of it.

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. True

  2. False

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Correct Option: B
Explanation:

Approximately for every litre of seawater there is $35$ $g$ of salt.

Salts are naturally found in seawater and salts are formed in the neutralization reaction.

Which of the following are efflorescent substances?

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. $Cu{SO} _{4}.5{H} _{2}O$

  2. ${Na} _{2}{CO} _{3}.10{H} _{2}O$

  3. ${K} _{2}{SO} _{4}.{Al} _{2}{({SO} _{4})} _{3}.24{H} _{2}O$

  4. ${({NH} _{4})} _{2}{SO} _{4}$

Show answer
Correct Option: A,B
Explanation:

An efflorescent substance is a chemical which has water associated with its molecules, and which, when exposed to air, loses this water through evaporation. An example of an efflorescent substance is the common copper(II) sulfate crystal $(CuSO _4.5H _2O)$, a blue crystalline solid that when exposed to air, slowly loses water of crystallization from its surface to crystallize to form a white layer of anhydrous copper(II) sulfate.


$Na _2CO _3.10H _2O$ loses 9 water molecules first and then becomes completely anhydrous. 

${K} _{2}{SO} _{4}.{Al} _{2}{({SO} _{4})} _{3}.24{H} _{2}O$ is not an efflorescent as its crystals do not lose water of crystallization by efflorescence nor it is oxidised in the air. ${({NH} _{4})} _{2}{SO} _{4}$ do not has associated water molecules.

Which of the following is deliquescent?

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. $ZnCl _2$

  2. $Hg _2Cl _2$

  3. $HgCl _2$

  4. $CdCl _2$

Show answer
Correct Option: A
Explanation:

$(A)$  $ZnCl _{2}$


$Reason$ : Zinc chloride is a chemical compound with the formula $ZnCl _{2}$ and its hydrates.All zinc chlorides are colourless or white and highly soluble in water.Zinc chloride or $ZnCl _{2}$ is a $deliquescent$ salt  and forms acidic solutions in polar organic solvents,such as water, ether and acetone etc.
As we know, $deliquescent$ substances are the water soluble substances which absorbs moisture from the air and then dissolve in the absorbed moisture to change into liquid state and this phenomenon is called $deliquescence$.$ZnCl _{2}$ is one of the example of $deliquescent$ substance.

$Na _2CO _3.10H _2O \longrightarrow Na _2CO _3.H _2O$

The given reaction is an example of:

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. efflorescent substance

  2. deliquescent substance

  3. hygroscopic substance

  4. none of the above

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Correct Option: A
Explanation:

In this reaction water is being released. This type of substance is known as efflorescent substance.

If there are three moles of $H _2O$ for every one mole of $LiClO _4$, what is the hydrate formula?

chemistry water drying and dehydrating agents hydrolysis of salts and the ph of their solutions chemical equilibrium and acids-bases

  1. $\displaystyle LiClO _4 \cdot 3H _2O $

  2. $\displaystyle 3LiClO _4 \cdot 3H _2O $

  3. $\displaystyle 3LiClO _4 \cdot H _2O $

  4. $\displaystyle LiClO _4 \cdot (H _2O) _3 $

  5. $\displaystyle 3(LiClO _4) \cdot 3(H _2O) _3 $

Show answer
Correct Option: A
Explanation:

If there are three moles of $H _2O$ for every one mole of $\displaystyle LiClO _4$. The hydrate formula would be $\displaystyle LiClO _4 \cdot 3H _2O $