Tag: chemistry

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Multiple choice chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

During the charging of lead accumulator battery voltage varies from:

  1. $2.15$ V to $1.88$ V
  2. $1.88$ V to $2.0$ V
  3. $1.88$ V to $2.15$ V

  4. does not change
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When the lead accumulator battery is charged, the voltage range is 1.88 V to 2.15 V as the concentration of sulphuric acid varies from 5% to 40%.


Hence, option C is correct.

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Calcium hydroxide $\xrightarrow {\Delta}$ Calcium oxide + water. Identify the type of chemical reaction:

  1. Decomposition Reactions

  2. Neutralization Reactions

  3. Displacement Reactions

  4. Combination Reactions
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The reaction Ca(OH)2 -> CaO + H2O is a decomposition reaction where a single reactant breaks down into two or more simpler products upon heating.

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Balance the reaction of copper sulphide with dilute hydrochloric acid. 

  1. ${ Cu } _{ 2 }S+2HCl\rightarrow { 2CuCl }+{ H } _{ 2 }S$
  2. ${ Cu } _{ 2 }S+HCl\rightarrow { CuCl }+{ H } _{ 2 }S$
  3. ${ Cu } _{ 2 }S+HCl\rightarrow { CuCl } _{ 2 }+{ H } _{ 2 }+{S}$
  4. $2{ Cu } _{ 2 }S+2HCl\rightarrow 2{ CuCl } _{ 2 }+{ S } _{ 2 }+{H} _{2}S$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Cu _2S+2HCl\longrightarrow 2CuCl+H _2S$

No. of Atom | No. of Atom | | --- | --- | --- | | $Cu$ |  $2$ | $2$ | | $S$ | $1$ | $1$ | | $H$ | $2$ | $2$ | | $Cl$ | $2$ | $2$ |

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Correct balanced equation from the following reactions is:

  1. $S + 3HNO _3 \rightarrow H _2SO _4 + NO _2 + 3H _2O$
  2. $S + HNO _3 \rightarrow H _2SO _4 + 2NO _2 + H _2O$
  3. $S + 3HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$
  4. $S + 6HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reaction:
$S + 6HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Give a balanced equation for thermal dissociation of a solid [both containing the chloride ion].

  1. $2{ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { N _2H _6}\left( g \right) +2HCl\left( g \right) $
  2. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +Cl _2\left( g \right) $
  3. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +H _2\left( g \right) $
  4. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +HCl\left( g \right) $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

On heating ammonium chloride above 340$^0$C it decomposes into mixture of ammonia and hydrochloric gas. It is a reversible reaction.
${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +HCl\left( g \right) $

Multiple choice chemistry metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

The term used to indicate the development of unpleasant smell and taste in fat and oil-containing foods due to aerial oxidation is:

  1. acidity

  2. radioactivity

  3. rabidity

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

The term used to indicate the development of unpleasant smell and taste in fat and oil containing foods due to aerial oxidation is rancidity.
The process of oxidizing fatty and oily substances is called as rancidity.

Multiple choice chemistry metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

The term 'rancidity' represents:

  1. acid rain

  2. oxidation of fatty food

  3. rottening of fruit

  4. fading of coloured clothes in the sun
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rancidity is a very general term and in its most general meaning, it refers to the spoilage of a food in such a way that it becomes undesirable (and usually unsafe) for consumption.During the process of oxidative rancidity, oxygen molecules interact with the structure of the oil and damage its natural structure in a way that can change its odor, its taste, and its safety for consumption.

Multiple choice chemistry metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Some oils and fats give a bad smell and taste because of  _________ .

  1. rancidity

  2. decomposition reaction

  3. hydrogenation reaction

  4. double displacement reaction

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rancidity is the oxidation of oils and fats changing their taste and smell. Specifically, it is the hydrolysis and/or auto-oxidation of fats into short-chain aldehydes and ketones which are objectionable in taste and odour.