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

Which of the following statement(s) is/are correct?

  1. Primary valency of the central metal of a complex is always satisfied by anions.

  2. Secondary valency of the central metal of a complex may be satisfied by either negative ions or neutral molecules.

  3. Species which show primary valencies in a complex compound can be precipitated out.

  4. None of the above
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

In short the Werner's theory may be stated as follows:

  1. The central metal in a complex possesses two types of valencies, primary or ionizable valency and secondary valency or non-ionizable valency.
  2. While the primary valency of the metal is variable, the secondary valency has a fixed value. The primary valency refers to the oxidation state and the secondary valency to the coordination number of the metal.
  3. The primary valency is satisfied by only negative ions whereas the secondary valency either by anions or neutral molecules or both.
  4. The secondary valencies are directed in space towards fixed positions around the neutral atom.
Hence, options A, B and C are correct.

Multiple choice biology simple nutrients into cells blood and its components components of blood composition of blood

Which one is the principal cation in the plasma of blood?

  1. $K^+$
  2. $Na^+$
  3. $Ca^{2+}$
  4. $Mg^{2+}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sodium is the most abundant electrolyte, and the most abundant cation, in blood plasma. Sodium plays a large role in maintaining water balance in the blood and in the tissues.The body monitors sodium and the volume of blood; sensors in certain parts of the body, such as the blood vessels and kidney, tell the kidneys whether to increase or decrease the excretion of sodium and water. Sodium also plays an important role in the functioning of nerve and muscle cells. Sodium and potassium traveling back and forth across the membranes of cells generate a charge, which can cause a muscle cell to contract or a nerve cell to transmit a signal.


So, the correct answer is 'Na+'.

Multiple choice biology simple nutrients into cells blood and its components components of blood composition of blood

The ion which is present maximum in blood plasma is

  1. K$^+$
  2. Ca$^{++}$
  3. Mg$^{++}$
  4. Na$^+$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Blood Plasma is the liquid portion of the blood. This is composed of water( 90%), ions, energy substrates, nutrients, metabolites,  antibodies, proteins, and lipoproteins. The most numerous cation in blood plasma is Na+, K+, Mg+, and Ca2+. However, Na+ is the main cation and is responsible for the plasma osmolarity.

Multiple choice biology simple nutrients into cells blood and its components components of blood composition of blood

The principal cation present in the blood plasma is

  1. $K^+$
  2. $Mg^{2+}$
  3. $Ca^{2+}$
  4. $Na^+$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The plasma is a faint yellow, slightly alkaline, somewhat viscous fluid. It consists of about 90% water, 1% inorganic salts in solution and 7 to 8 % proteins in the colloidal state. The remaining 1% is formed by food materials, waste products, dissolved gases etc. The inorganic salts occur in plasma as ions. Sodium and chloride are the principal cation and anion of the plasma respectively. Thus, the correct answer is option D.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

Which of the following is not true about the ionic solids?

  1. Bigger ions form the close packed structure.

  2. Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.

  3. Occupation of all the voids is not necessary.

  4. The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In ionic solids anions (which are normally longer in size than cations forms closed pack array. 

The cation occupies one of the two types of holes remaining between the anions (either tetrahedral void or octahedral void). 
Depending on the relative sizes of cations and anions, the voids are filled. Occupation of voids depends on the stoichiometry of the compounds. It is not necessary that all voids get filled.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

$KCl(s)$ is:

  1. An ionic substance

  2. A polar covalent substance

  3. A nonpolar covalent substance

  4. An amorphous substance

  5. A metallic network
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Potassium chloride KCl is a metal halide salt composed of potassium and chloride. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water and its solutions have a salt-like taste.


In aqueous solution,

$KCl\longrightarrow { K }^{ + }+{ Cl }^{ - }$

It is an ionic substance in solid state.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

Which of the following ionic solids has the lowest melting point?

  1. $KCl$
  2. $NaCl$
  3. $LiF$
  4. $LiCl$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Melting point of an ionic compound is determined by the electrostatic attraction between cations and anions. It takes a lot of energy to overcome this attraction to allow the ions to move freely and form a liquid. The factor witch effect melting point is charge of the ion. Since, $KCl$ has $+1$ and $-1$ charge on its' cations and anions respectively. Hence, it has the lowest melting point.


Hence, the correct option is $A$

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

Metallic bonding is explained by :

  1. band model

  2. electron-sea model

  3. both (a) and (b)

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

Both theories have their own arguments to explain metallic bonding.
Each metal atom allows its electrons to roam freely, so these atoms become positively charged cations. These cations are kind of like a positively charged island and are surrounded by a sea of negatively charged electrons.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

Which of the following molecules has polar bonds but is a nonpolar molecule?

  1. $H _{2}$
  2. $H _{2}O$
  3. $NH _{3}$
  4. $NaCl$
  5. $CO _{2}$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Carbon dioxide $\displaystyle CO _2 $ has polar bonds but is a nonpolar molecule. The structure of $\displaystyle  CO _2$  is linear. The individual bond dipoles cancel each other as they point in opposite direction and are equal in magnitude. Hence, the molecule is non polar with zero dipole moment.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

In the ionic solid $NH _4NO _3$, ions present are:

  1. $NH _4^+$ and $NO^- _3$
  2. $N^{5+}, H^+$ and $O^{2-}$
  3. $NH _4^-, N^{5+}$ and $O^{2-}$
  4. $NH _3, H^+$ and $NO _3^-$
  5. $N^{5+}, N^{3-}, H^+$ and $O^{2-}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the ionic solid ammonium nitrate $NH _4NO _3$,  ions present are ammonium $NH _4^+$   and nitrate $NO^- _3$. Strong electrostatic force of attraction is present between oppositely charged ions.