Chemistry

Chemical Reactions and Processes

626 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 p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Which one of the following processes does not yield anhydrous $ AlCl _3 $?

  1. Heating of $ AlCl _3 . 6H _2O $.

  2. Passing dry HCl over heated aluminium powder.
  3. Passing dry $ Cl _2 $ over heated aluminium powder.
  4. Heating a mixture of alumina and coke in a current of dry $ Cl _2 $.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$ 2AlCl _3 . 6H _2O \xrightarrow {\Delta} Al _2O _3 + 6HCl + 9H _2O $ .

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

Aluminum hydroxide is used for :

  1. fire extinguishers

  2. antacid

  3. water purification

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aluminum hydroxide is an interesting base, because it has a wide number of applications, including its use in antacids. As such, it reacts with and neutralizes stomach acid, and for that reason is found in commercial antacids. It is useful in fire extinguishers as a foaming agent. Aluminum hydroxide is also used in water purification, in dyeing garments, and in the production of certain kinds of glass.

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

In which of the following, neutralisation reaction takes place?

  1. Treatment of acid or basic salt

  2. Treatment of acidic effluents

  3. Treatments of gastic patients

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

Treatment of gastric patients, treatment of acidic effluents from factory wastes and treatment of acid/base salts, are examples of neutralization in everyday life. Hence, D

Multiple choice chemistry air and water pollution control smoke, dust and other air pollutants, acid rain air pollutants and its effects air and air pollution

Which of the following is a characteristic of hydrogen sulphide?

  1. Poisonous

  2. Flammable

  3. Explosive

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

Hydrogen sulfide is the chemical compound with the formula $H _2S$. It is a colorless gas with the characteristic foul odor of rotten eggs; it is heavier than air, very poisonous, corrosive, flammable, and explosive.

Multiple choice chemistry air and water pollution control smoke, dust and other air pollutants, acid rain air pollutants and its effects air and air pollution

What is released when hydrogen sulphide burns in oxygen?

  1. Hydrogen gas

  2. Water

  3. Sulphur trioxide

  4. Sulphur dioxide
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

$2H _2S+3O _2\longrightarrow \underbrace {2SO _2} _{sulphur\quad dioxide}+\underbrace {2H _2O} _{water}$

When hydrogen sulphide burns in oxygen, formation of sulphur dioxide and water takes place.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen does not combine with ______.

  1. Sb

  2. Na

  3. He

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

Since Helium (He) is a noble gas and does not combines with hydrogen. Because bond formation is only favored when the final state of the two elements is more stable than their initial state. If a hydrogen atom bonded with a helium atom, neither of their 1s and 2s atomic orbital will be half/fully filled, which causes both atoms to be energetically unstable. Such compound will most likely break down immediately back to their respective atomic state.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen loses its electron to form $H^+$. In this respect, it resembles:

  1. halogens

  2. alkali metals

  3. transition element

  4. alkaline earth metals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alkali metals have one electron present in their outer shell in group I so after losing one electron they become stable ions similarly hydrogen has lone electron in its shell after losing it shares the same character as alkali metal group.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen is :

  1. electropositive

  2. electronegative

  3. both electronpositive 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.
Like alkali metals, H has tendency to lose its one valency electron to form unipositive hydrogen ion $H^+$.
Hence, hydrogen is electropositive in nature.
Like halogens, hydrogen has tendency to gain one electron and form uninegative ion $H^-$.
Hence, hydrogen is electronegative in nature.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen behaves as a metal:

  1. at low temperature

  2. at low pressure

  3. at high temperature

  4. at high pressure
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metallic hydrogen is a phase of hydrogen when it behaves as electrical conductor. At the high pressure of gigapascals hydrogen might exist as a liquid metal. Liquid metallic hydrogen is thought to be present in large amount in gravitationally compressed interiors of Jupiter and Saturn.

Multiple choice chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

The reaction of zinc metal and $HCl$ produces which of the following?
i. $H _2(g)$
ii. $Cl _2(g)$
iii. $ZnCl _2(aq)$

  1. ii only

  2. iii only

  3. i and ii only

  4. i and iii only

  5. i, ii and iii
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Zn being an active metal it readily reacts HCl at room temperature.

$Zn+HCl\rightarrow ZnCl _{ 2 }+{ H } _{ 2 }$
It is a diplacement reation. 
Zinc displaces hydrogen from $HCl$.