Chemistry

Chemical Reactions and Processes

571 Questions

Chemical reactions and processes questions cover the transformation of substances through electrolysis, thermal decomposition, and catalysis. Key areas include identifying gas evolution, balancing chemical equations, and understanding industrial chemical applications. This general chemistry topic is a staple in the science sections of multiple competitive examinations.

Thermal decompositionElectrolysis processGas evolution reactionsHeterogeneous catalystsFuel cell components

Chemical Reactions and Processes Questions

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Why does baking soda and vinegar react with each other?

  1. Undergo acid base reaction

  2. Exchange atoms
  3. Both $(A)$ and $(B)$

  4. High temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Baking soda and vinegar react with each other because of an acid-base reaction. Baking soda is a bicarbonate $(NaHCO _{3})$ and vinegar is an acetic acid $(HCH _{3}COO)$. One of the products this reaction creates is carbon dioxide. Also Baking soda and vinegar react with each other because they exchange atoms. In this case, they are exchange a proton, which is a subatomic particle that makes atoms.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

When sulphuric acid reacts with calcium carbonate, ________ is formed.

  1. calcium sulphate

  2. calcium

  3. calcium hydroxide

  4. hydrogen gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sulphuric acid gives calcium sulphate, carbon dioxide gas and water when it reacts with calcium carbonate.
$CaC{O} _{3}   +   {H} _{2}S{O} _{4}   \rightarrow   CaS{O} _{4}   +   C{O} _{2}   +   {H} _{2}O$.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Why do the gas released when metal bicarbonates react with acid turns lime water milky?

  1. Formation of calcium hydrogen carbonate

  2. Precipitation of calcium hydrogen carbonate

  3. Formation of white calcium carbonate precipitate

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

When metal bicarbonates react with acid liberates carbon dioxide The gas evolved because of reaction of acid with metal carbonate or metal hydrogen carbonate turns lime water milky. This shows that the gas is carbon dioxide gas. This happens because of formation of white precipitate of calcium carbonate.
$Ca{\left(OH\right)} _{2}  + C{O} _{2}    \Rightarrow   CaC{O} _{3}  +  {H} _{2}O$.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

What is used with acid in fire extinguisher to produce carbon dioxide gas?

  1. Metal oxide

  2. Metal hydrogen carbonate

  3. Metallic acid

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

Metal carbonate or metal hydrogen carbonate and acid are used in fire extinguisher to produce carbon dioxide gas. Acid and metal carbonate or bicarbonate are kept in separate chambers in a fire extinguisher. On emergency, they are allowed to react with one another. The carbon dioxide gas so produced is poured over fire. As carbon dioxide does not support burning, it puts off the fire.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

The gas released when $NaHCO _3$ reacts with $HNO _3$ will:

  1. turn lime water milky

  2. release effervescence
  3. both $A$ and $B$

  4. burns with a pop sound
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

On adding a hydrogen carbonate to an acid, effervescence from carbon dioxide gas is released along with the formation of water and salt. $CO _2$ turns lime water milky.
$ NaHCO _3 + HNO _3 \rightarrow NaNO _3 + H _2O + CO _2 $

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:

  1. $NaCl$
  2. $HCl$
  3. $LiCl$
  4. $KCl$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Crushed egg shell has composition $CaCO _3$ reacts with acid and gives gas $CO _2$ which turns lime water $(Ca(OH) _2)$ milky by producing $CaCO _3$ again. The acid in given options is $HCl$. 

$CaCO _3 + 2HCl \rightarrow CaCl _2 + CO _2 + H _2O $
$Ca(OH) _2 + CO _2 \rightarrow CaCO _3 + H _2O$

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Which of the following represents the products obtained when, $HCl$ reacts with sodium hydrogen carbonate?

  1. $NaCl$, $H _2O$ and $CO _2$
  2. $NaCl$ and $CO _2$
  3. $NaOH$ and $CO _2$
  4. $NaOH$, $H _2O $ and $CO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When $HCl$ reacts with sodium hydrogen carbonate, the products obtained are $NaCl,$ $H _2O$ and $CO _2$.
$\displaystyle NaHCO _3 + HCl \rightarrow NaCl + H _2O + CO _2$

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

When an acid reacts with a metal carbonate or metal hydrogen carbonate, it gives the corresponding salt, gas and product. Name the gas and product?

  1. Carbon dioxide, Water

  2. Carbon dioxide, Salt

  3. Hydrogen, Salt

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Acid + Metal carbonate  $\longrightarrow$ Salt + Water + Carbon dioxide

CaCO$ _3$ (calcium carbonate-metal carbonate) + 2HCl $\longrightarrow$ CaCl$ _2$ (calcium chloride-salt) + H$ _2$O + CO$ _2$

Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

For which of the following reactions, is Gay Lussac's law not applicable?

  1. Formation of $HI$ from its constituents
  2. Formation of $NH _3$ from its constituents
  3. Formation of $CO _2$ from its constituents
  4. Formation of $SO _3$ from $SO _2$ and $O _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gay Lussac's law not applicable to formation of $CO _{2}$ from its constituents as carbon and oxygen exist in different physical states.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

The hydride ion, $H^{-}$ is a stronger base than its hydroxide ion $OH^{-}$. Which of the following reactions will occur, if sodium hydride $(NaH)$ is dissolved in water?

  1. $H^{-} _{\left ( aq \right )}+H _{2}O\rightarrow H _{3}O^{-}$
  2. $H^{-} _{\left ( aq \right )}+H _{2}O _{\left ( l \right )}\rightarrow OH^{-}+H _{2}$
  3. $H^{-}+H _{2}O _{(l)}\rightarrow\ no\ reaction$
  4. $None\ of\ the\ above$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sodium hydride $(NaH)$ react with water to form hydrogen gas and the sodium hydroxide $(NaOH)$.
$NaH+H _2O\rightarrow H _2+NaOH$
i.e., $Na^+, H^-$ and $H^+, OH^- $ give rise to $H _2$ and $NaOH$. So, it is similar to option B.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Which of the following metals directly combine with hydrogen gas to give a hydride? 

  1. Au

  2. Ni

  3. Ca

  4. Cu
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Amongst, $Au$, $Ni$, $Ca$ and $Cu$, $Ca$ is the most reactive metal. So it easily combines with $H _2$ to form hydride while the other metals do not combine directly.


The reaction can be given as:-
$Ca+H _2\longrightarrow CaH _2$

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Non-stoichiometric hydrides are produced by:

  1. palladium, vanadium

  2. manganese, lithium

  3. nitrogen, filorine

  4. carbon, nockel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The hydrogen deficient compounds formed by the reaction of $d-block$ and $f-block$ elements with dihydrogen are called Non-stoichiometric compounds. 

The d-block and f-block element form non-stoichiometric hydride because of the vacant d- and f-orbitals along with the small size.
Their elemental composition proportions cannot be represented in integers. They disobey the law of constant composition. Among the elements given, only vanadium and palladium form non-stoichiometric hydrides.


Answer: (A) palladium, vanadium

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Hydrogen is:

  1. electropositive

  2. electronegative

  3. both electropositive as well as electronegative

  4. neither electropositive nor electronegative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Hydrogen is both electropositive as well as electronegative, as it forms hydrogen ion $H^+$ as well as hydride ion $H^-$.
Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Hydrogen readily combines with these elements?

  1. Na

  2. K

  3. Ca

  4. Zn
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

${ H } _{ 2 }$ easily reacts with $Na, Ca, K$ as they are highly reactive metals and are placed at the top of the reactivity series.

${ 2Na }+{ H } _{ 2 }\rightarrow 2NaH$
$2K+{ H } _{ 2 }\rightarrow 2KH$
$Ca+{ H } _{ 2 }\rightarrow CaH _2$.