Tag: substances in common use

Questions Related to substances in common use

$Ca(H _{2}PO _{4}) _{2}$ in baking powder:

  1. Behaves as an acid in moist condition and decomposes $NaHCO _{3}$ to give $CO _{2}$

  2. Behave as a base in moist condition and gives $H _{3}PO _{4}$

  3. Behaves as binder

  4. Behaves as a filler


Correct Option: A
Explanation:

The baking powder consists of sodium bicarbonate and calcium dihydrogen phosphate.In this process the ${ H } _{ 2 }{ PO } _{ 4 }$ acts as acid in the baking powder and then reacts with ${ NaHCO } _{ 3 }$  so that carbon dioxide that expands in the food items.When sufficient heat is given bond will breaks between  $Ca$ and ${ H } _{ 2 }{ PO } _{ 4 }$ and then reacts with 

$NaHC{ O } _{ 34 }$ and the carbon dioxide will be formed.

When sample of baking soda is strongly ignited in crucible it suffered loss in weight of  $3.1 g $  the mass of baking soda is- 

  1. $ 16.8 g $

  2. $ 8.4 g $

  3. $ 11.6 g $

  4. $4.2 g $


Correct Option: B
Explanation:
The reaction is:
$2NaHCO _3 \rightarrow Na _2CO _3+H _2O+CO _2$

The loss in weight is due to water and carbon dioxide.

$2$ moles $(2\times 84 g)$ of sodium bicarbonate gives $ 1$  mole $( 18  g)$ of water and $ 1$ mole of carbon dioxide $( 44 g)$.

Thus, decomposition of $ 168   g$ of sodium bicarbonate will result in loss in weight of $18+44=62g$

The loss in weight of $3.1$ g corresponds to $\dfrac{168}{62}\times 3.1=8.4g$ of sodium bicarbonate. 

Option B is correct.

Which of the following is known as fusion mixture?

  1. mixture of $Na _{2}CO _{3}+NaHCO _{3}$

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

  3. mixture of $K _{2}CO _{3}+Na _{2}CO _{3}$

  4. $NaHCO _{3}$


Correct Option: C
Explanation:

fusion mixture consists of a sodium salt and a potassium salt. Generally, mixture of potassium carbonate and sodium carbonate is used. It is called a fusion mixture because it is fused with a sample of organic compound to test for various groups.

Hence option C having both sodium carbonate and potassium carbonate is the correct answer.

Read the given statements and select the correct option:


Statement 1 :Backing soda does not taste sour.
Statement 2 :Bases are sour in taste while acids are bitter in taste.

  1. Both statements 1 and 2 are true statement 2 is correct explanation of statement 1.

  2. Both statements 1 and 2 are true both statement 2 is not the correct explanation of statement 1.

  3. Statements 1 is true and statement 2 is false

  4. Both statements 1 and 2 are false.


Correct Option: C
Explanation:

Baking soda,which has chemical name sodium bicarbonate $(NaHCO _3)$ is slightly basic in nature.Which means it tastes bitter as acid taste sour and bases taste bitter.

Statement 01: $NaHCO _3$ does not taste sour  is correct.
Statement 02: Acid taste bitter and bases taste sour is wrong.

Baking powder contains :

  1. $NaHCO _{3}, Ca(H _{2}PO _{2}) _{2}$ and starch

  2. $NaHCO _{3}, Ca(H _{2}PO _{2}) _{2}$

  3. $NaHCO _{3}$, starch

  4. $NaHCO _{3}$


Correct Option: A
Explanation:

Baking powders contains sodium bicarbonate and one or more acid salts. Usually 30% sodium bicarbonate, 5-12% monocalcium phosphate, and 21-26% sodium aluminium sulfate and starch.

The baking soda formula is :

  1. $K _{2}CO _{3}$

  2. $NaHCO _{3}$

  3. both a and b

  4. none of these


Correct Option: B
Explanation:

Its chemical formula is $NaHCO _3$(sodium bicarbonate). Its formula consists of one sodium (Na) atom, one hydrogen (H) atom, one carbon (C) atom and three oxygen (O) atoms. It is commonly known as baking soda, bread soda, bicarbonate of soda, and cooking soda.

$\text{Statement}:$ Baking soda or baking powder is different.


Answer whether the above statement is true or false.

  1. True

  2. False


Correct Option: A
Explanation:
$\text {Baking soda}$ has only one ingredient: sodium bicarbonate. It's chemical formula is $NaHCO _3$ and dissolves into water in its ionic form: $Na^+$ and $HCO^{3-}$. Sodium bicarbonate is a base that reacts when it comes into contact with acids, like buttermilk, yogurt or vinegar. 

Baking powder has different ingredients that create $CO _2$ gas at different stages of the baking process. A typical formulation (by weight) could call for 30% sodium bicarbonate, 5–12% monocalcium phosphate, and 21–26% sodium aluminium sulphate.

Baking soda and Baking powder can be distinguished by the ingredients present as well as their reactivity towards acids.

Hence, the given statement is True.

The pair whose both species are used in antacid medicinal preparation is

  1. $NaHCO _3$ and $Mg(OH) _2 $

  2. $Na _2CO _3$ and $Ca(HCO _3) _2 $

  3. $Ca(HCO _3) _2$ and $Mg(OH) _2 $

  4. $Ca(OH) _2$ and $NaHCO _3$


Correct Option: A
Explanation:

Milk of magnesia is an aqueous suspension of magnesium hydroxide $[Mg(OH) _2]$ used to treat acid indigestion.
Also sodium bicarbonate is used for antacid 
medicinal preparation.

When we add a pinch of sodium hydrogen carbonate in a flask containing ethanoic acid a reaction takes place. What will be the observation when we carry out the reaction?

  1. Milky solution

  2. Bubble formation

  3. Solution turns red

  4. Brisk effervescence


Correct Option: D
Explanation:
Two main observations during the reaction are:
(i) Brisk effervescence
(ii) Sodium acetate is formed

Chemical equation for the reaction is:

$2CH _3COOH + 2NaHCO _3 \to 2CH _3COONa + 2CO _2 + 2H _2O$


Option D is correct.

'Sodium bicarbonate solution has $pH$ less than 7.'
State True or False:

  1. True

  2. False

  3. Cannot be determined

  4. None of the above


Correct Option: B
Explanation:

Sodium bicarbonate is amphoteric, reacting with acids and bases. It reacts violently with acids, releasing CO2 gas as a reaction product. Because of $NaHCO _3$ is a weak base the pH value should be greater than 7.

Reaction with sulfuric acid: 
$2 NaHCO _3 + H _2SO _4 \rightarrow Na _2SO _4 + 2 H _2O + 2 CO _2$ 

With sodium hydroxide: 
$NaHCO _3 + NaOH \rightarrow Na _2CO _3 + H _2O$

Hence, statement is false.