Chemistry · Electrochemistry
Work through this past-paper style MCQ, then read the full explanation. Practice more chemistry questions on mMCQ with adaptive drills and topic analytics.
In the given reaction CH₃OH → HCOOH, oxidation state of carbon changes from:
- A
-2 to 0
- B
-2 to +2
- C
-3 to +2
- D
0 to +2
The reaction CH₃OH → HCOOH involves the oxidation of methanol to formic acid. In methanol (CH₃OH), the carbon atom has an oxidation state of -2. Upon oxidation to formic acid (HCOOH), the oxidation state of carbon increases to +2. Therefore, the change in oxidation state is from -2 to +2, which is correctly represented by Option B.
Other options are incorrect because:
- Option A states a change from -2 to 0, which does not occur.
- Option C suggests a change from -3 to +2, which misidentifies the oxidation state in methanol.
- Option D indicates a change from 0 to +2, which is not accurate as the starting oxidation state is -2.
This option suggests that the oxidation state of carbon changes from -2 to 0, which is incorrect. In methanol (CH₃OH), the oxidation state of carbon is -2, but in formic acid (HCOOH), it does not reach 0.
This is the correct option. In methanol (CH₃OH), the oxidation state of carbon is -2, and in formic acid (HCOOH), the oxidation state of carbon changes to +2.
This option incorrectly states that the oxidation state changes from -3 to +2. The carbon in methanol has an oxidation state of -2, not -3.
This option is incorrect because it suggests that the oxidation state changes from 0 to +2. The carbon in methanol has an oxidation state of -2, not 0.
Tagged under Chemistry · Electrochemistry · 2025