Identify the incorrect statement from the followinga)The oxidation num...
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Identify the incorrect statement from the followinga)The oxidation num...
Incorrect Statement: The oxidation number of K in KO2 is 4.
Explanation:
The correct oxidation number of potassium (K) in KO2 is +1, not +4. Let's break down the given options to understand why this statement is incorrect.
a) The oxidation number of K in KO2 is 4.
- This statement is incorrect. In KO2, the oxygen (O) atoms have an oxidation number of -1 each, and since the compound is electrically neutral, the potassium (K) atom must have an oxidation number of +1 to balance the charges. Therefore, the correct oxidation number of K in KO2 is +1.
b) Ionisation enthalpy of alkali metals decreases from top to bottom in the group.
- This statement is correct. The ionization enthalpy of alkali metals generally decreases from top to bottom in the group. This is because as we move down the group, the atomic size increases, which leads to a decrease in the effective nuclear charge experienced by the outermost electron. As a result, it becomes easier to remove the outermost electron, leading to a decrease in ionization enthalpy.
c) Lithium is the strongest reducing agent among the alkali metals.
- This statement is correct. Lithium (Li) is the strongest reducing agent among the alkali metals. This is because lithium has the highest tendency to lose its outermost electron and get oxidized. It has the lowest ionization enthalpy and the highest electrode potential among the alkali metals, making it the strongest reducing agent.
d) Alkali metals react with water to form their hydroxides.
- This statement is correct. Alkali metals react vigorously with water to form their respective hydroxides and hydrogen gas. The reaction is highly exothermic, releasing a large amount of heat. For example, when potassium (K) reacts with water, it forms potassium hydroxide (KOH) and hydrogen gas (H2).
In conclusion, the incorrect statement is option 'a' which states that the oxidation number of K in KO2 is 4. The correct oxidation number of K in KO2 is +1.
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