Daseous nyarogen burns in the presence of oxygen to form water:
[tex]2 H_2+O_2 \rightarrow 2 H_2 O+ \text { energy }[/tex]
Which molecule is oxidized and what kind of bond is formed?
A. Oxygen, polar.
B. Hydrogen, polar.
C. Oxygen, nonpolar.
D. Hydrogen, nonpolar.
Answer (2)
In the reaction, hydrogen is oxidized as its oxidation state increases from 0 to +1. The bonds formed in water (H₂O) are polar covalent due to the difference in electronegativity between hydrogen and oxygen. Thus, the correct answer is B. Hydrogen, polar.
;
Hydrogen is oxidized because its oxidation state increases from 0 in H 2 to +1 in H 2 O .
The bond formed between hydrogen and oxygen in water ( H 2 O ) is a polar covalent bond due to the difference in electronegativity between oxygen and hydrogen.
Therefore, the answer is Hydrogen, polar.
$\boxed{Hydrogen, polar.}
Explanation
Problem Analysis In the given chemical reaction, we need to identify which molecule is oxidized and the type of bond formed in the product, water ( H 2 O ). Oxidation involves an increase in oxidation state, while reduction involves a decrease.
Determining Oxidation States Let's determine the oxidation states of hydrogen and oxygen before and after the reaction:
In H 2 , the oxidation state of hydrogen is 0.
In O 2 , the oxidation state of oxygen is 0.
In H 2 O , the oxidation state of hydrogen is +1, and the oxidation state of oxygen is -2.
Identifying Oxidized Molecule Since the oxidation state of hydrogen increases from 0 to +1, hydrogen is oxidized. The oxidation state of oxygen decreases from 0 to -2, meaning oxygen is reduced.
Determining Bond Type Water ( H 2 O ) is formed by covalent bonds between oxygen and hydrogen atoms. Oxygen is more electronegative than hydrogen, resulting in unequal sharing of electrons. This electronegativity difference creates a polar covalent bond.
Examples
Understanding oxidation and reduction is crucial in many real-world applications. For example, the rusting of iron involves the oxidation of iron atoms in the presence of oxygen and water. Similarly, batteries rely on redox reactions to generate electricity, where one material is oxidized (loses electrons) and another is reduced (gains electrons). In the human body, metabolic processes involve a series of oxidation-reduction reactions that provide energy for cells to function. These reactions are essential for life, highlighting the importance of understanding oxidation states and electron transfer. For example, when we eat food, our bodies break it down through oxidation to release energy, with oxygen acting as the oxidizing agent.
