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 metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Four metals $P$, $Q$, $R$ and $S$ react with water as given below:
I. $P$ reacts with cold water
II. $Q$ reacts with hot water
III. $R$ reacts with steam
IV. Red hot $S$ reacts with steam.
Then, highly reactive metal is:

  1. $P$
  2. $Q$
  3. $R$
  4. $S$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The highly reactive metal is $P$ as it reacts with cold water. This is because, the reaction with cold water requires lowest energy of activation.

Multiple choice commercial applications global environmental change causes of resource depletion causes of greenhouse effect ozone layer depletion

HCs are thermodynamically not stable towards

  1. Acidification

  2. Decomposition

  3. Reduction

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

Hydrocarbons (HCs) are generally susceptible to oxidation reactions, especially in the presence of oxygen or oxidizing agents, which is why they are not thermodynamically stable in such environments.

Multiple choice chemistry chemistry of non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

Platinum metal can be dissolved in:

  1. hot conc. HCl
  2. hot conc. $HNO _3$
  3. hot dil. $H _2SO _4$
  4. a mixture of conc. HCl and $HNO _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Traditional aqua regia is a mixture of concentrated nitric and hydrochloric acids in a ratio of 1:3 that can dissolve noble metals such as gold, platinum and palladium, even though the metals are not soluble in either acid alone.
  • Hence option D is correct answer.
Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

Statement 1: When HCl gas and $NH _3$ gas come into contact, a white smoke forms.
Statement 2: $NH _3$ and HCl react to form a white solid, ammonium chlorate.

  1. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.</p>

  2. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.</p>

  3. <p>Statement 1 is correct but Statement 2 is not correct.</p>

  4. <p>Statement 1 is not correct but Statement 2 is correct.</p>

  5. <p>Both the Statement 1 and Statement 2 are not correct.</p>
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When ammonia and $HCl$ come in contact, they form ammonium chloride.
$\displaystyle  NH _3+HCl \rightarrow NH _4Cl$

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

Compound which on heating with sodium hydroxide produces a gas which forms dense white fumes with hydrogen chloride?

  1. Chlorine

  2. Lead carbonate

  3. Ammonium sulphate

  4. Iron [II] sulphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ammonium sulphate is the compound formed which on heating with sodium hydroxide produces a gas which forms dense white fumes with hydrogen chloride.

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

When $Na$ reacts with liquid $NH _3$ the following substance is formed: 

  1. $[Na(NH _3) _x]^- $
  2. $ [e(NH _3 ) _y]^-$
  3. $NaNH _2$
  4. $Na _xNH _{3y}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sodium (Na) dissolves in liquid ammonia ($NH _3$) solution to form a blue colored solution characteristic of a solvated electron in liquid ammonia which is conducting in nature due to presence of solvated electrons.

Reaction is  $ Na + (x+y)NH _3\rightarrow Na(NH _3) _x + (e(NH _3) _y)^-$
So B is correct answer. 

Multiple choice

Oxygen acts as final hydrogen acceptor

  1. True

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

In aerobic respiration, oxygen is the final electron acceptor in the electron transport chain, where it combines with electrons and protons to form water.

Multiple choice

When an acid and an alkali react together:

  1. a salt and water are both produced

  2. only a salt is produced.

  3. a metal is formed

  4. a gas is given off
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The reaction between an acid and an alkali (a base) is a neutralization reaction, which always produces a salt and water.

Multiple choice

When an acid reacts with a metal carbonate, the products are:

  1. the metal and carbon dioxide

  2. a salt and water

  3. carbon dioxide, water and a salt.

  4. the metal, a salt and water.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The general word equation for the reaction between an acid and a metal carbonate is: acid + metal carbonate -> salt + water + carbon dioxide.

Multiple choice

If an acid reacts with a metal, the products are:

  1. a salt and water

  2. a salt and hydrogen gas

  3. only hydrogen gas

  4. a salt, water and carbon dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The general word equation for the reaction between a metal and an acid is: metal + acid -> salt + hydrogen gas.

Multiple choice

When some acid is put onto a piece of metal:

  1. there is always a reaction which burns a hole in the metal.

  2. there is never a reaction

  3. some metals will react and produce bubbles of gas.

  4. there is always a reaction, which produces a powder
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Not all metals react with acids (e.g., copper or gold do not react with dilute acids). For those that do, the reaction typically produces a salt and hydrogen gas, which appears as bubbles.