Tag: substances in common use

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Questions Related to substances in common use

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

Which of the following give brisk effervescence with baking soda ?

  1. methanoic acid

  2. propanoic acid

  3. ethanoic acid

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

$NaHCO _{3}$ 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 $100^{o}C$. 

  1. $CO _{2}$
  2. $H _{2}O$

  3. both (a) and (b)

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

$NaHCO _{3}$ 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 :

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

  3. acts as filler

  4. makes the bread rise.
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

$NaHCO _{3}$ 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:

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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 $CO _2$

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

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

  1. ${H NO _3}$
  2. $HCl$
  3. ${Cl _2}$
  4. ${H _2SO _4}$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

The solution of bleaching powder in water is always a clear solution.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bleaching powder is known as calcium hypochlorite. It is marketed as bleach powder. It is white solid although commercial samples appear yellow. It is not highly soluble in water and is used in soft to medium hard water. It has two forms dry and hydrated.

Multiple choice chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

Bleaching powder is effective with cold water, but ineffective with hot water. This is because of:

  1. oxidation of chloride radical

  2. reduction of chloride radical

  3. reduction of hypochlorite radical

  4. hydrolysis of hypochlorite radical
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bleaching action takes place due to the hypochlorite radical [$ClO^{-}$].

But when used in hot water, hot water favours reduction of the hypochlorite radical as a result of which bleaching powder is ineffective with hot water.
Generally, Bleaching powder is used as a disinfectant widely.