Chemistry

Chemical Bonding and Molecular Structure

1,277 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 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.

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

 Least boiling point is of:

  1. ethylene glycol

  2. ether

  3. water

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

Ether has least boiling point as it cannot form hydrogen bonds. Ethylene glycol, water and phenol can form intermolecular hydrogen bonds which lead to intermolecular hydrogen bonding and high boiling points. Hydrogen bonding is possible when $H$ atom is attached to electronegative $N,\ O$ or $F$ atom.

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

Ethers show dipolar nature due to the presence of ______.

  1. central C atom

  2. central O atom

  3. central N atom

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ethers have general structural formula R-O-R'. Hence all of them have the C-O bond. We know that the C-O bond is polar due to the difference between the electronegativities of carbon and oxygen. Hence, ethers show dipolar 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 exists in atomic state in which of the following compounds?

  1. Metallic hydrides

  2. Ionic Hydride

  3. Molecular hydrides
  4. ${ H } _{ 2 }O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Metal hydrides are metals which have been bonded to hydrogen to form a new compound. Any hydrogen compound that is bonded to another metal element can effectively be called a metal hydride. Generally, the bond is covalent in nature, but some hydrides are formed from ionic bonds.
  • Hence option A is a correct answer.
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

Among I-A elements which can form ionic as well as covalent bonds? 

  1. Hydrogen

  2. Cerium

  3. Helium

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

Hydrogen is the lightest element on the periodic table. Hydrogen forms covalent compounds with non metals. In ionic compounds hydrogen can take the form of negative charge when it is known as hydride or a cation.

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 differs from elements of $I-A$ group as:

  1. it can form ionic as well as covalent bond

  2. all are metals
  3. $ H^+$ is unstable in water
  4. both $A$ and $B$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The options A and B are the correct answers.
Hydrogen differs from elements of $I-A$ group as:
(A) hydrogen can form ionic as well as covalent bond whereas elements of $I-A$ group can form only ionic bonds.
(B) All elements of $I-A$ group are metals. Hydrogen (with very high ionization energy does not possess metallic character).
(C) $H^+$ ion is stable in water.

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

Which of the one is correct about Hydrogen?

  1. resembles in IA since it forms monovalent cation $H^+$.
  2. resembles in VIIA (halogen family) since it forms monovalent anion $H^-$.

  3. resembles in IVA(carbon family) since both have a half filled shell of electron

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

In HCl, H has + 1 oxidation state so it resembles IA group property.


In NaH, H has -1 oxidation state so it resembles VIIA group property. 

H due to half-filled s shell of electron it resembles IVA group property.

So option D is the correct answer. 

Multiple choice chemistry the p-block elements - group 13 study of orthoboric acid some important compounds of boron study of boron

$2B+3H _{2}SO _{4}\rightarrow 2H _{3}BO _{3} +A$ 


The hybridization of central atom in compound A is :

  1. sp
  2. $sp^{2}$
  3. $sp^{3}$
  4. $sp^{3}d$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The balanced chemical reaction is as given below.
$2B+3H _{2}SO _{4}\rightarrow 2H _{3}BO _{3}\rightarrow + \underset {A} {SO _2}$
S atom in sulphur dioxide undergoes $sp^2$ hybridization.

Multiple choice chemistry the p-block elements - group 13 study of orthoboric acid some important compounds of boron study of boron

The states of hybridisation of boron and oxygen atoms in boric acid $(\mathrm{H} _{3}\mathrm{B}\mathrm{O} _{3})$ are respectively:

  1. $\mathrm{s}\mathrm{p}$ and $\mathrm{s}\mathrm{p}^{2}$
  2. $\mathrm{s}\mathrm{p}^{2}$ and $\mathrm{s}\mathrm{p}^{3}$
  3. sp3 and $\mathrm{s}\mathrm{p}^{2}$

  4. sp3 and sp3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The states of hybridisation of boron and oxygen atoms in boric acid $(\mathrm{H} _{3}\mathrm{B}\mathrm{O} _{3})$ are respectively are $\mathrm{s}\mathrm{p}^{2}$ and $\mathrm{s}\mathrm{p}^{3}$
respectively.

In boric acid the boron is surrounded by three bond pair thus it shows $sp^2$ hybridization while oxygen is surrounded by one two bond pair and two lone pairs so it shows $sp^3$ hybridization.