Chemistry

Chemical Bonding and Molecular Structure

1,420 Questions

This section tests your knowledge of chemical bonding, molecular structure, and hybridization. It covers ionic and covalent bonds, octet rule exceptions, and molecular geometry. These chemistry questions are common in various competitive entrance examinations.

Ionic and covalent bondsHybridisation of elementsOctet rule exceptionsMolecular geometryIntermolecular forces

Chemical Bonding and Molecular Structure Questions

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Aluminium (III) chloride forms a dimer because aluminium :

  1. cannot form a trimer.

  2. has high ionization energy.

  3. belongs to third group.

  4. can have higher coordination number.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 Aluminium trichloride is a dimer, $Al _2Cl _6$.

This is because: 
$AlCl _3$ forms a dimer as there is unsaturation in coordination. Also it enables Al atoms to complete their octets.

Aluminium is more like a metalloid than a metal.The electronegativity of aluminium is higher than the electronegativity of sodium .


Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

Which of the following is a Lewis acid?

  1. $AlCl _3$
  2. $MgCl _2$
  3. $CaCl _2$
  4. $BaCl _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$Al$ needs two more electrons to complete its octet, it has the tendency to accept a pair of electrons to achieve stable electronic configuration. By definition, those which accepts electrons are called lewis acids. 

Thus, $Al{Cl} _{3}$ is a Lewis acid.


Hence, the correct answer is option $\text{A}$.

Multiple choice chemistry environmental chemistry biochemistry and the environment green chemistry strategies to control environmental pollution and green chemistry

Which of the following compounds are toxic?

  1. Benzene

  2. Toluene

  3. Carbon tetrachloride

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

A toxic substance is a substance that can be poisonous or cause health effects.

Benzene is known to cause cancer, based on evidence from studies in both people and lab animals.Basically it is carcinogenic.
Toluene is irritating to the skin, eyes, and respiratory tract. It can cause systemic toxicity by ingestion or inhalation and is slowly absorbed through the skin.
Carbon tetrachloride is one of the most potent hepatotoxins (toxic to the liver), so much so that is widely used in scientific research to evaluate hepatoprotective agents.Exposure to high concentrations of carbon tetrachloride (including vapour) can affect the central nervous system, degenerate the liver and kidneys and prolonged exposure may lead to coma or death.

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

Which base is employed as the electrolyte in alkaline batteries?

  1. $Ca(OH) _2$
  2. $Al(OH) _3$
  3. $FeOH$
  4. $KOH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aqueous potassium hydroxide is employed as the electrolyte in alkaline batteries based on nickel-cadmium, nickel-hydrogen, and manganese dioxide-zinc. Potassium hydroxide is preferred over sodium hydroxide because its solutions are more conductive.

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.

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

Which of the following are used as free radical chain initiators ?

  1. Benzoyl peroxide

  2. di-tert-butyl peroxide

  3. Carbon tetrachloride

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

A radical initiator is a species that acts as the reactant of the initiation step of a radical chain reaction but does not participate in any of the propagation steps.
Radical initiators are substances that can produce radical species under mild conditions and promote radical reaction. These substances generally possess weak bonds that have small bond dissociation energy. Radical initiators are utilized in industrial processes such as polymer synthesis. Typical examples are halogen molecules, azo compounds and organic and inorganic peroxides such as Benzoyl peroxide, di- t-Butyl peroxide.

Multiple choice chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

If the two members of a Dobereiner's triad are chlorine and iodine, then the third member of this triad is :

  1. fluorine

  2. bromine

  3. sodium

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

According to Dobereiner, the atomic mass of the middle element is nearly equal to the arithmetic mean of the other two. Therefore, the atomic mass of the third element is $=$ $\dfrac{{35.5}+{127}}{2}$ $=$ 81.25, which is the atomic mass of bromine.

Multiple choice chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

The law of triads is not applicable to :

  1. $Os, Ir, Pt$
  2. $Ca, Sr, Ba$
  3. $Fe, Co, Ni$
  4. $Ru, Rh, Pt$
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

The law of triads does not apply to $Ru, Rh, Pt$.


According to the law of triads, the atomic weight of the middle element is approximately equal to the arithmetic mean of the other two elements.

The atomic weights of $Ru, Rh$ and $Pt$ are $101, 102.9$ and $195$ respectively.

The arithmetic mean of the atomic weights of $Ru$ and $Pt$ is $\displaystyle \dfrac {101+195}{2} = 148$
Hence, the atomic weight of $Rh$ is not equal to the arithmetic mean of the atomic weights of $Ru$ and $Pt$.

$Fe = 56, Co = 59$ and $Ni = 59$

Mean of the weights of $Fe$ and $N$i is not equal to the weight of $Co$.


Hence, the correct options are $\text{C}$ and $\text{D}$

Multiple choice chemistry hydroxy compounds and ethers physical properties of ethers ethers alcohols, phenols and ethers

The compound which has highest boiling point among the following is: 

  1. diethyl ether

  2. ethanol

  3. methanol

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

Boiling point of Diethyl ether $=34.6^0C$


Boiling point of Ethanol $=78.5^0C$

Boiling point of Methanol $=64.7^0C$

Boiling point of Water $=100^0C$

Hydrogen bonding in water and alcohol due to which they have higher boiling points.

Here, water has the highest boiling point among others.

 So correct answer is option D.