Tag: chemistry

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Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Which acids/ bases are used for the following?
(i) To neutralize sting of wasps
(ii) In alkaline batteries
(iii) Manufacturing of soap

  1. (i) $CH _3CHO$ (ii) $CsOH$ (iii) $Ca(OH) _2$
  2. (i) $CH _3COOH$ (ii) $CuSO _4$ (iii)$ Ba(OH) _2$
  3. (i) $CH _3COOH$ (ii) $KOH$ (iii)$ NaOH$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  1. Formic acid is produced by ants and acetic acid is used as anti-wasp agents.
    2. In alkali batteries a base is used as an electrolyte which gives hydroxyl ions in solution.
    3. Manufacturing of soap requires an alkali like $NaOH$ and long chain of fatty acids like sodium stearate to form an ester or sodium acetate salt.
Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

$X+H _2O\rightarrow Y$. 

$Y$ is used to remove grease stains from woollen clothes. Identify $X$ and $Y$.

  1. $X=HCl, Y=NaOH$
  2. $X=NH _4OH, Y=NH _3$
  3. $X=NH _3, Y=NH _4OH$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ammonia solution is good for removing stains and tarnish and can also repel moths and reduce paint odours. As ammonia reacts with the water, it is dissolved in to produce ammonium ions and hydroxide ions.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Indigestion is painful so to relieve indigestion, we take an antacid such as milk of magnesia , which 
contains :

  1. magnesium hydroxide

  2. hydrochloric acid

  3. tartaric acid

  4. calcium hydroxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Milk of magnesia (also known as magnesium hydroxide; $ { Mg }{ (OH) } _{ 2 } $) is basic in nature and one of the most important ingredients of an antacid. 


The hydroxide ions from $ { Mg }{ (OH) } _{ 2 } $) undergo neutralisation with $ { H }Cl $ in the stomach produced during indigestion or gastric problems, to produce water. Equation is as follows :

$ \quad 2HCl\quad +\quad Mg{ (OH) } _{ 2 }\quad \rightarrow \quad Mg{ (Cl) } _{ 2 }\quad +\quad 2{ H } _{ 2 }O $


Hence the option A is correct.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Ant bite is treated by application of __________.

  1. washing soda

  2. baking soda

  3. neutral solution

  4. acidic solution
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The venom ant bites are acidic in nature. So, it's effects can be neutralised by bicarbonate of soda such a baking soda or an alkali (basic in nature). 


Hence the correct option is B.

Multiple choice chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

Determine the degree of association (polymerization) for the reaction in aqueous solution
$6HCHO\rightleftharpoons C _6H _{12}O _6$
If observed (mean) molar mass of HCHO and $C _6H _{12}O _6$ is $150$.

  1. $0.50$
  2. $0.833$
  3. $0.90$
  4. $0.96$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Let us consider the problem.
$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, 6HCHO \,\,\,\,\,\leftrightarrow {C _6}{H _{12}}{O _6}$
At equation $c\left( {1 - \alpha } \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\dfrac{{C\alpha }}{6}$
$\dfrac{{Observed\,moles\,concentration}}{{Initial\,moles\,concentration}} = \dfrac{{{M _\gamma }}}{{{M _0}}}$
$\dfrac{{C\left( {1 - \alpha } \right) + \dfrac{{C\alpha }}{6}}}{C} = \dfrac{{{M _\gamma }}}{{{M _0}}} = \dfrac{{30}}{{150}}$
Hence the answer is $\alpha  = 0.96$
Multiple choice chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

The monomer that undergo radical polymerisation most easily is ?

  1. $CH _2=CH _2$
  2. $C _6H _5CH=CH _2$
  3. $CH _2=C{(Me)} _2$
  4. $CH _3-CH=CH _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethylene (CH2=CH2) is the simplest monomer and undergoes radical polymerization most readily because it lacks steric hindrance and has no substituents that would stabilize or destabilize the radical intermediate significantly compared to substituted monomers.

Multiple choice chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

Which one of the following polymer is step-growth polymer

  1. Polythylene
  2. Nylon-$66$
  3. Buna-$S$ rubber

  4. Orlon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Step-growth polymers, often formed by condensation reactions between bifunctional monomers, include polymers like Nylon-6,6. Polyethylene, Buna-S rubber, and Orlon are chain-growth or addition polymers formed through radical or ionic mechanisms. Thus, Nylon-6,6 is the correct step-growth polymer.

Multiple choice chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

Which of the following free radicals is the most stable ?

  1. primary

  2. methyl

  3. secondary

  4. tertiary
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electron poor species are stabilized by neighboring atoms that can donate electron density. The most common way to interpret rich neighbors here is the observation that increasing the number of alkyl groups on the carbon bearing the free radical increases its stability. 


Radical stability increases in the order methyl < primary < secondary < tertiary. 

Hence, option $D$ is correct.