Question

Consider the following type of bonds: (1) ionic (2) covalent (3) coordinate (4) hydrogen bond Which type of bonds are present in \(\mathrm{NaHCO}_{3} ?\) (a) 1 and 3 (b) 2 and 4 (c) 1 and 2 (d) 1,2 and 3

Short answer

The bonds present in \(\mathrm{NaHCO}_{3}\) are ionic, covalent, and coordinate (d).

Step-by-step solution

Identify the Compound's Composition

Sodium bicarbonate, \(\mathrm{NaHCO}_{3}\), consists of sodium (Na), hydrogen (H), carbon (C), and oxygen (O).

Determine Possible Bonds

Evaluate each type of bond: 1. **Ionic Bond**: Typically found between metals and non-metals. 2. **Covalent Bond**: Found between non-metal atoms sharing electrons. 3. **Coordinate Bond**: A type of covalent bond where one atom supplies both electrons in the bond formed. 4. **Hydrogen Bond**: A weak bond between a hydrogen atom and an electronegative atom like oxygen or nitrogen.

Analyze Bonding between Na and HCO₃

Sodium (Na), a metal, and the bicarbonate ion (HCO₃⁻), a polyatomic ion, form an ionic bond. This is because Na donates an electron to the HCO₃⁻ ion.

Explore Internal Bonding in HCO₃⁻

Within the bicarbonate ion (HCO₃⁻), the bonds involve shared electrons between non-metal atoms (H, C, O), confirming covalent bonding due to the nature of the atoms involved and electron sharing required to form HCO₃⁻.

Check for Presence of Coordinate Bonds

In bicarbonate ions, there is a scenario where oxygen atoms can form coordinate bonds with the central carbon by donating a lone pair of electrons to form a double bond or similar interactions involving lone pairs.

Final Bond Type Determination

Combining these observations: - Ionic bond: between Na and HCO₃⁻.- Covalent bond: within the HCO₃⁻ ion among H, C, and O.- Coordinate bond: potential within HCO₃⁻ ion due to electron donation by oxygen.Thus, the bonds present in \(\mathrm{NaHCO}_{3}\) are ionic, covalent, and coordinate (1, 2, and 3).

Key concepts

Ionic Bond

Ionic bonds are a fundamental aspect of chemical bonding often formed between metals and non-metals. This type of bond arises when a metal, such as sodium (Na) in the compound \( \text{NaHCO}_3 \), donates electrons to a non-metal or a polyatomic ion, such as carbonate (\( \text{HCO}_3^- \)).
For instance, in sodium bicarbonate, sodium (Na) loses one electron to become \( \text{Na}^+ \), while \( \text{HCO}_3^- \) gains this electron to maintain its overall charge. This transfer of electrons leads to the formation of an electrostatic attraction that holds the metal and non-metal together. Such electrostatic forces are the hallmark of ionic bonds.
The strength of ionic bonds often results in compounds that have high melting and boiling points. These bonds create a strong lattice structure and are typically soluble in water, allowing ionic compounds to conduct electricity when dissolved.

Covalent Bond

Covalent bonds occur when two non-metal atoms share electrons. This type of bond is prevalent in various compounds, where it helps form stable molecules. Within \( \text{NaHCO}_3 \), the atoms of hydrogen (H), carbon (C), and oxygen (O) in \( \text{HCO}_3^- \) are connected by covalent bonds.
Covalent bonding involves the sharing of electron pairs between atoms. For example, carbon is a central atom in \( \text{HCO}_3^- \) and forms covalent bonds with three oxygen atoms to fulfill its octet. One of these oxygen atoms is also bonded to a hydrogen atom, resulting in the formation of \( \text{-OH} \) group.
A covalent bond's strength is influenced by the involved atoms' electronegativities and the bond length; shorter and stronger bonds form with higher electronegativity differences. Covalent compounds can be gases, liquids, or solids, often having lower melting and boiling points compared to ionic compounds. However, these bonds create more specific, directional interactions, giving rise to diverse molecular geometries.

Coordinate Bond

A coordinate bond, also known as a dative covalent bond, is a variation of the covalent bond where both electrons in the shared pair come from one atom. This type of bonding can also be found in \( \text{HCO}_3^- \).
In this scenario, a lone pair of electrons from an oxygen atom is used to form a coordinate bond with carbon, which typically involves forming a double bond. This makes it a vital component of the compound's internal structure, allowing for stability and electron pair sharing, essential for the formation of molecules like bicarbonate ions.
Coordinate bonds allow compounds to exhibit interesting properties, often enabling transition between different molecular configurations or contributing to the flexibility and reactivity of the ions. Understanding coordinate bonds helps in recognizing complex bonding interactions in coordination chemistry and molecular structures.