Tag: chemical equilibrium and acids-bases

Questions Related to chemical equilibrium and acids-bases

$NaCl + H _2SO _4\overset{\Delta}{\longrightarrow}HCl \ +$

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

  1. $NaHSO _4$

  2. $Na _2SO4$

  3. $Na _2SO _3$

  4. none of the above

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Correct Option: A
Explanation:

Reacting sodium chloride and sulphuric acid at elevated temperature leads to production of sodium bisulphate and hydrogen chloride. Little amount of sodium sulphate is also formed which reacts with the sulphuric acid to yield sodium bisulphate or sodium hydrogen sulphate.
$NaCl\left( s \right) +{ H } _{ 2 }{ SO } _{ 4 }\rightarrow { NaHSO } _{ 4 }\left( s \right) +HCl$

Identify the correct representation of reaction occurring during chloro-alkali process. 

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

  1. $2NaCl(l)+ 2H _2O(l) \rightarrow 2NaOH(l) + Cl _2(g) + H _2(g)$

  2. $2NaCl(s)+ 2H _2O(aq) \rightarrow 2NaOH(aq) + Cl _2(g) + H _2(g)$

  3. $2NaCl(aq)+ 2H _2O(l) \rightarrow 2NaOH(aq) + Cl _2(aq) + H _2(aq)$

  4. $2NaCl(aq)+ 2H _2O(l) \rightarrow 2NaOH(aq) + Cl _2(g) + H _2(g)$

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Correct Option: D
Explanation:

Chloro-alkali process is an industrial process for the electrolysis of sodium chloride. It is used to produce chlorine and sodium hydroxide. Aqueous sodium chloride or brine ina membrane cell.


At cathode: ${ 2H } _{ 2 }O+2{ e }^{ - }\rightarrow { H } _{ 2 }+{ 2OH }^{ - }$ 

At anode: $2{ Cl }^{ - }\rightarrow { Cl } _{ 2 }+2{ e }^{ - }$ 


$2NaCl(aq)+2{ H } _{ 2 }O\rightarrow { Cl } _{ 2 }(g)+{ H } _{ 2 }(g)+2NaOH(aq)$


Option $(D)$ suggests the correct reaction.

Addition of large quantity of Iron salt will coagulate blood.

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: A
Explanation:
Addition of large quantity of Iron salt will coagulate blood. A trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently form soluble plasma fibrinogen (FBG) into an insoluble fibrin clot.

The chemical that changes its colour when it is left open in sunlight is:

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

  1. $FeSO _4\, (s)$

  2. $Pb(NO _3) _2\, (s)$

  3. $AgCl\, (s)$

  4. $BaCl _2\, (aq)$

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Correct Option: C
Explanation:

$AgCl\, (s)$ colors changes when exposed in sunlight.

Which of the following salts when dissolved in water would give acidic solution(s)?

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

  1. $Na _2SO _4$

  2. $(NH _4) _2SO _4$

  3. $CH _3COONa$

  4. $KCI$

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Correct Option: B
Explanation:

Ammonium sulfate reacts with water to form sulfuric acid which is highly acidic in nature as it completely dissociates to give hydrogen ions.

What are the products formed when an aqueous solution of magnesium bicarbonate is boiled?

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

  1. $MgCO _3,\, H _2O,\, CO _2$

  2. $Mg(HCO _3) _2,\, H _2O$

  3. $Mg(OH) _2,\, H _2O$

  4. $Mg,\, CO _2,\, H _2O$

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Correct Option: A
Explanation:

When magnesium bicarbonate is boiled $MgCO _3, H _2O$ and $CO _2$ are formed. A small amount of $Mg(OH) _2$ is also formed.

Reaction: $Mg(HCO _ 3) _2\xrightarrow[\Delta]{} MgCO _ 3+H _ 2O+CO _ 2+Mg(OH) _ 2$

Which of the following salts on heating gives a mixture of two gases?

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

  1. $Ba(NO _3) _2$

  2. $NaNO _3$

  3. $KNO _3$

  4. $RbNO _3$

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Correct Option: A
Explanation:

$(A)$  $Ba(NO _3) _2$


$Reason$ :  The elements in the group 2 includes beryllium($Be$), magnesium($Mg$), calcium($Ca$), strontium($Sr$), barium($Ba$) and radium($Ra$).
The group 2 nitrates, on heating, gives metal oxide, nitrogen dioxide and oxygen gas.
For example - $2Ba(NO _3) _2(s)$ $\rightarrow$ $2BaO(s)$ + $4NO _2(g)$ + $O _2(g)$
Group 2 nitrates also become more thermally stable down the group. 

When hydrated $MgCl _2.\, 6H _2O$ is strongly heated:

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

  1. $MgO$ is formed

  2. $Mg(OH) _2$ is formed

  3. $Mg(OH)Cl$ is formed

  4. Ahydrous $MgCl _2$ is formed

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Correct Option: A
Explanation:

Magnesium hydrochloride is hygroscopic in nature and it loses its water molecules with the formation of magnesium oxide. When mixed with hydrated magnesium oxide, magnesium chloride forms a hard material called Sorel cement.

The correct order of pH is

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

  1. Lemon juice < water < Milk of Magnesia

  2. Lemon juice> water> Milk of Magnesia

  3. Water > lemon juice > milk of Magnesia

  4. Milk of Magnesia > lemon juice > water

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Correct Option: A
Explanation:

Milk of magnesia is basic, water is neutral and lemon juice is acidic in nature.

A salt derived from strong acid and weak base will dissolve in water to give a solution which is :

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

  1. acidic

  2. basic

  3. neutral

  4. none of the above

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Correct Option: A
Explanation:

In neutralization reaction the strong acid with weak base reaction the solution becomes acidic in nature as the salt formed in it alongwith water.