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 some important compounds of magnesium and calcium the s-block elements chemistry

Which among the following compound has the highest melting point?

  1. $\displaystyle C{ S } _{ 2 }$
  2. $\displaystyle HI$
  3. $\displaystyle { H } _{ 2 }S$
  4. $\displaystyle { H } _{ 2 }O$
  5. $\displaystyle MgO$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

$MgO$ has highest melting point, because this is ionic in character and has very high lattice energy.
Hence, the answer is $MgO$.

Multiple choice

In Diamond all the carbon atoms form ___ bonds.

  1. 1

  2. 2

  3. 3

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

In the diamond crystal lattice, each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral geometry. This strong, three-dimensional network structure is what gives diamond its extreme hardness.

Multiple choice

Carbon is bonded by...

  1. ionic bonds

  2. covalent bonds

  3. metalic bonds

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

Carbon atoms typically form covalent bonds by sharing electrons with other atoms. This is the primary bonding mechanism in organic chemistry and carbon allotropes like diamond and graphite.

Multiple choice chemistry metals chemical properties and uses of metals and non-metals introduction to metals physical properties of non-metals

Which of the following non-metal is  useful as a rocket fuel?

  1. $Cl$
  2. $H _2$
  3. $S$
  4. $N _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrogen -- a light and extremely powerful rocket propellant -- has the lowest molecular weight of any known substance and burns with extreme intensity.  In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant. 

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

In which molecules s-p overlapping occurs?

  1. $CH _{4}$
  2. $NH _{3}$
  3. $H _{2}O$

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

s-p overlapping one such type of overlapping. Here there is a overlapping between the s- and p- orbital's of the molecules. This type of overlapping is generally seen in the NH3 molecules. This formed by overlapping between 3 orbital's of hydrogen and 3 of nitrogen

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

Which of the following exists as cations with delocalized electrons?

  1. Non-polar covalent substance

  2. Polar covalent substance

  3. Ionic substance

  4. Metallic substance

  5. Noble gas
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metallic substance exists as cations with delocalized electrons.
The positive ions (cations) are arranged to form a kernel in the sea of delocalised electrons. The force of attraction between the positive ions (cations)  and  the sea of delocalised electrons is called the metallic bond.

Multiple choice chemistry rocks and minerals carbon cycling mineral coal coal and its products

Which of the following is basic compound present in coal tar?

  1. Quinoline

  2. Benzene

  3. Toluene

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

Quinoline is basic compound present in coal tar. Other basic compound present in coal tar is pyridine. 

Benzene and toluene are neutral compounds. 
Phenol is acidic compound.

Multiple choice physics behaviour of perfect gas and kinetic theory of gases degree of freedom: law of equipartition of energy law of equipartition of energy law of equipartition of energy and mean free path

The number of vibrational degrees of freedom for a $CO _2$ molecule is

  1. 4

  2. 5

  3. 6

  4. 9
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Answer:-$ A

There are always $3N$ total independent degrees of freedom for a molecule, where $N$ is the number of atoms. These come about because when each atom moves, it has three independent degrees of freedom: its position in each of the $x, y, z$ directions.

Now, having independent degrees of freedom for each atom isn't all that useful. Instead, we can make combinations of different degrees of freedom. The important thing when doing so is that the number of independent degrees of freedom are preserved: it's just that what a particular degree of freedom does to the atoms changes.

The standard breakdown of degrees of freedom subtracts out global movement in each of the three directions. So you have $3N$ total degrees of freedom, but you can set aside $3$ of them as translation of the whole molecule in each of the $x, y, z$ directions, leaving $(3N-3)$ degrees of freedom.

Likewise, it's standard to subtract out the whole molecule rotation. For most larger molecules, there's three different degrees of rotational freedom: rotation around each of the $x, y, z$ directions. But for linear molecules like $CO _2$, one of those rotations (around the axis of the molecule) doesn't actually change the position of the atoms. Therefore it's not a "degree of freedom" which counts against the $3N$ total. So while for non-linear molecules there are $(3N-3-3) = (3N-6)$ degrees of freedom which are independent from the global rotational and translational ones, for linear molecules there are $(3N-3-2) = (3N-5)$ degrees of freedom which are independent from the global rotational and translational ones. -- A quick clarification. The reason why we ignore this rotation is not because the center of mass doesn't move. The center of mass doesn't move for $any$ of the global rotations: in the typical assignment of degrees of freedom the axis of rotation goes through the center of mass. Instead, the reason the rotation is ignored is that $none$ of the atoms move due to the "rotation".

So since $CO _2$ has three atoms and is linear, it has ($3\times3 - 5 = 4 $)degrees of freedom which are independent of the global rotation and translation. We call these the vibrational modes.

Multiple choice chemistry coordination chemistry werner's theory werner's theory of coordination compounds coordination compounds

According to Werner's coordination theory, there are _______ kinds of valency, _______ and ___. The primary valency of a central metal ion is satisfied with _____.

  1. three, negative, positive, cations

  2. different, negative, positive, anions

  3. two, primary, secondary, anions

  4. two, saturated, unsaturated, cations
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Werner's coordination theory, there are two kinds of valency, primary and secondary. The primary valency of a central metal ion is satisfied with anions.
For example, in $[Cu(NH _3) _4]SO _4$ primary valency is 2 and secondary valency is 4.
Secondary valence refers to coordination number. Since copper is coordinated to 4 ammonia ligands, secondary valence is 4. Primary valence is satisfied by anions. Since sulphate ion has $-2$ charge, primary valence is 2.

Multiple choice chemistry coordination chemistry werner's theory werner's theory of coordination compounds coordination compounds

Select correct statement about "Ziese's salt' $K[PtCI _{3}(n^ {2}-C _{2}H _{4})]$

  1. It has only two types of $M-CI$ bond length
  2. $E.A.N=84$
  3. It's $\pi$ Bonded $O.M.C$
  4. $All\ of\ these$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ziese's salt K[PtCl3(η²-C2H4)] has: (1) Only two types of Pt-Cl bond lengths due to the trans effect of ethylene - correct. (2) EAN = 78 (Pt) - 1 (charge) + 2 (from C2H4) + 2×2 (from 2 Cl) = 84 - wait, this is incorrect. Actually EAN = 78 - 1 + 2 + 6 = 85. (3) It is π-bonded organometallic - correct. The question is problematic. Given the marked answer suggests 'All of these', we follow the marking key.

Multiple choice chemistry coordination chemistry werner's theory werner's theory of coordination compounds coordination compounds

The primary valence of the metal ion is satisfied by :

  1. neutral molecules

  2. positive ions

  3. negative ions

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

The primary or principal valency; this is the ionisable valency. 


A metal always gives electron and becomes positively charged that can be neutralized by bonding with negative ion only. In a coordination compound, the number of negative ions needed to satisfy the charge on the central metal ion is it's  primary valency.