Tag: compounds of carbon

Questions Related to compounds of carbon

Washing soda on strong heating gives sodium oxide and carbon dioxide.

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. True

  2. False

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Correct Option: A
Explanation:

$Na _2CO _3 (s) \rightarrow Na _2O (s) + CO _2 (g)$
From the above reaction, it shows that washing soda ($Na _2CO _3$) on heating gives sodium oxide and carbon dioxide.

Sodium hydrogen carbonate is used in fire extinguisher.

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. True

  2. False

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Correct Option: A
Explanation:

 Sodium hydrogen carbonate or sodium bicarbonate is used as a fire extinguisher. When heated to a high temperature, the chemical properties of this salt make it produce lots of carbon dioxide and remove oxygen. This reduces the amount of oxygen and puts the fire out. The reaction also produces a small quantity of water and sodium carbonate as by-products.
$2NaHCO _3 + H _2SO _4 \rightarrow Na _2SO _4 + 2H _2O + 2CO _2$

Solution of sodium hydrogen carbonate is alkaline in nature.

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. True

  2. False

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Correct Option: A
Explanation:

Solution of sodium hydrogen carbonate is mildly alkaline due to the formation of carbonic acid and hydroxide ion:
$ HCO _3 + H _2O \rightarrow H2CO _3 + OH-$ 

Chemical formula of baking soda is:

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. $MgSO _4$

  2. $Na _2CO _3$

  3. $NaHCO _3 $

  4. $MgCO _3$

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Correct Option: C
Explanation:

Chemical formula of baking soda is $NaHCO _3$.

Which of the following give brisk effervescence with baking soda ?

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. methanoic acid

  2. propanoic acid

  3. ethanoic acid

  4. all of these

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Correct Option: D
Explanation:

The carboxylic acids react with baking soda to form sodium acetate, carbon dioxide and water. The general reaction can be written as:
$RCOOH + NaHCO _{3} \rightarrow CH _{3}COONa + CO _{2} + H _{2}O$
Thus the effervescence results from the release of carbon dioxide gas.

$NaHCO _{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO _{3}$, $Ca(H _{2}PO _{4}) _{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO _{3}$ 20% $NaAl(SO _{4}) _{2}$ and 10% $Ca(H _{2}PO _{4}) _{2}.$ 

Answer the following questions based on above study.

Rise in bread and cakes is due to______ when it decomposes between $50^{o}C$ and $100^{o}C$. 

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. $CO _{2}$

  2. $H _{2}O$

  3. both (a) and (b)

  4. none of these

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Correct Option: A
Explanation:
This happens due to reaction: $NaHCO _3+ H^+ \rightarrow Na^+ + CO _2+ H _2O$ 

The carbon dioxide produced in these reactions causes the dough to rise (ferment or prove), and the alcohol produced mostly evaporates from the dough during the baking process.

$NaHCO _{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO _{3}$, $Ca(H _{2}PO _{4}) _{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO _{3}$ 20% $NaAl(SO _{4}) _{2}$ and 10% $Ca(H _{2}PO _{4}) _{2}$

Answer the following questions based on above study.


In improved baking powder, $NaAl(SO _{4}) _{2}$ is used for :

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. makes the decomposition of $NaHCO _{3}$ faster

  2. slows the decomposition of $NaHCO _{3}$

  3. acts as filler

  4. makes the bread rise.

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Correct Option: B
Explanation:

Acid in a baking powder can be either fast-acting or slow-acting. $NaAl(SO _4) _2$ is a weak acid, it react with sodiumbicarbonate to produce $CO _2$ gas.

$NaAl(SO _4) _2 + 3NaHCO _3 \rightarrow AlOH _3 + 2Na _2SO _4 + 3CO _2$

$NaHCO _{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO _{3}$, $Ca(H _{2}PO _{4}) _{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO _{3}$ 20% $NaAl(SO _{4}) _{2}$ and 10% $Ca(H _{2}PO _{4}) _{2}.$ 

Answer the following questions based on above study.

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

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

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

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

  3. behaves as a binder

  4. behaves as a filler

Show answer
Correct Option: A
Explanation:

Reaction of process:
$14 NaHCO _3+ 5 Ca(H _2PO _4)2H _2O\rightarrow 14 CO _2+ Ca _5(PO _4)3OH + 7 Na _2HPO _4+ 18 H _2O$


So Ca(H2PO4)2 in baking powder behaves as an acid  in moist condition and decomposes $NaHCO _3$ to give $CO _2$

${NaHCO _3+?\rightarrow NaCl+CO _2+H _2O}$ :

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. ${H NO _3}$

  2. $HCl$

  3. ${Cl _2}$

  4. ${H _2SO _4}$

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Correct Option: B
Explanation:

When sodium bicarbonate reacts with $HCl$, chlorine binds with sodium and forms sodium chloride and bicarbonate ion binds with hydrogen ion of $HCl$ and forms carbonic acid. The carbonic acid further dissociates to water and carbon dioxide.

 $NaHCO _3$ is used as fire extinguisher.

chemistry allotropy of carbon preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. True

  2. False

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Correct Option: A
Explanation:

Fire extinguisher contains sodium bicarbonate in water and sulphuric acid in a separate container inside it. When the fire extinguisher is released by pressing the knob on it, the sulphuric acid mixed with sodium bicarbonate solution producing a lot of carbon dioxide gas.

$2NaHCO _3 + H _2SO _4\rightarrow Na _2SO _4 + 2H _2O + 2CO _2$ 

Carbon dioxide gas is neither combustible nor helps in combustion. It is heavier than air and offs the supply of oxygen from air and hence removes the fire. So, sodium bicarbonate is used in fire extinguishers. So the given statement is true.

Hence option A is correct.