Problem 89 - A Complete Resource Book in Chemistry for JEE Main

Question

Among the following compounds which contain all 3 type of bonds (i) \(\mathrm{NH}_{4} \mathrm{Cl}\) (ii) \(\mathrm{K}_{3} \mathrm{Fe}(\mathrm{CN})_{6}\) (iii) \(\mathrm{H}_{2} \mathrm{O}_{2}\) (iv) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (v) \(\mathrm{CaCO}_{3}\) (a) I, II (b) I, II, V (c) I, II, IV (d) I, II, III

Step-by-Step Solution

Answer

The correct answer is (a) I, II.

Step 1: Identify the Type of Bonds

Identify the ionic, covalent, and coordinate (dative) bonds present in each compound. - 10: 10: has ionic bond between  ext{NH}_{4}^{+} and  ext{Cl}^{-}, covalent bonds within  ext{NH}_4^{+}, and coordinate bond in the formation of 104: molecule. - 0: K3: has ionic bonds between K^{+} and  ext{Fe}( ext{CN})_6^{3-}, covalent bonds within  ext{CN}^{-}, and coordinate bonds between  ext{Fe} and  ext{CN}^{-}. - 3: has only covalent bonds. - 4: has covalent, coordinate bonds between O and HSO4 and S, and no ionic bonds. - 5: has ionic bond between  ext{Ca}^{2+} and  ext{CO}_3^{2-}, covalent bonds within  ext{CO}_3^{2-} but no coordinate bonds.

Step 2: Select Compounds with All Three Types of Bonds

From the above observations, identify compounds that contain all three types of bonds: ionic, covalent, and coordinate. - 10: contains ionic, covalent, and coordinate bonds. - acknowledgements: contains ionic, covalent, and coordinate bonds. - None of the others contain all three types of bonds.

Step 3: Choose the Correct Option

Given the options, option (b) I, II, V suggests that compounds  ext{NH}_{4} ext{Cl}, K_3 ext{Fe}( ext{CN})_6, and  ext{CaCO}_{3} contain all three types of bonds. However, as discussed,  ext{CaCO}_{3} does not contain coordinate bonds. Thus, option (b) is incorrect. Option (a), I, II correctly list compounds that contain all three types of bonds.

Key Concepts

Ionic Bonds

Ionic bonds occur when one atom donates an electron to another atom, resulting in the formation of positively and negatively charged ions. These opposite charges attract each other, creating a strong bond. This can be thought of as a give-and-take relationship between atoms.

Common characteristics of ionic bonds include:

• Formation between metals and non-metals.
• High melting and boiling points due to the strong attraction between ions.
• Typically forms crystalline solids.

In the context of our original exercise, \(\mathrm{NH}_{4}\mathrm{Cl}\), for example, shows an ionic bond between the \(\mathrm{NH}_{4}^{+}\) ion and a \(\mathrm{Cl}^{-}\) ion. Similarly, in \(\mathrm{K}_{3}\mathrm{Fe}(\mathrm{CN})_{6}\), potassium ions (\(\mathrm{K}^{+}\)) interact with the negatively charged complex ion \(\mathrm{Fe}(\mathrm{CN})_{6}^{3-}\) to form ionic bonds.

Covalent Bonds

Covalent bonds form when two atoms share electrons, allowing them to obtain a stable electron configuration, similar to that of noble gases. This type of bond is common in organic compounds and can occur between atoms of the same element or different elements.

Key features of covalent bonds include:

• Formation between non-metals with similar electronegativities.
• Often results in the formation of molecules.
• Lower melting and boiling points compared to ionic compounds.

Within the given compounds, covalent bonds are found in \(\mathrm{NH}_{4}^{+}\) due to the sharing of electrons among nitrogen and hydrogen atoms. In \(\mathrm{K}_{3}\mathrm{Fe}(\mathrm{CN})_{6}\), covalent bonds are present within the \(\mathrm{CN}^{-}\) ions as carbon and nitrogen share electrons.

Coordinate Bonds

Coordinate bonds, also known as dative bonds, occur when both electrons in the shared pair originate from the same atom. This type of bond is a special case of covalent bonding. Once formed, a coordinate bond is indistinguishable from a regular covalent bond.

Features of coordinate bonds:

• Often formed between a metal ion and a ligand.
• Involves one atom donating a lone pair to another atom.
• Common in complex ions and coordination compounds.

In the context of our exercise, \(\mathrm{NH}_{4}\mathrm{Cl}\) exhibits a coordinate bond where the nitrogen atom donates a pair of electrons to form \(\mathrm{NH}_{4}^{+}\). For \(\mathrm{K}_{3}\mathrm{Fe}(\mathrm{CN})_{6}\), coordinate bonds are observed between the iron (Fe) and cyanide (CN) ligands.