When ethanol reacts with potassium dichromate, which one of the following is produced ?

When ethanol (a primary alcohol) reacts with acidified potassium dichromate (K2Cr2O7), it undergoes a controlled oxidation process. Potassium dichromate acts as a strong oxidizing agent [1][t2]. The reaction typically proceeds in two stages: ethanol is first oxidized to ethanal (acetaldehyde), which is then further oxidized to ethanoic acid, commonly known as acetic acid [t2][t5]. The chemical equation for this transformation is 3C2H5OH + 2Cr2O7^2- + 16H+ → 3CH3COOH + 4Cr^3+ + 11H2O [t8]. During this process, the orange dichromate ions are reduced to green chromium(III) ions [t5]. While acetaldehyde can be an intermediate, the final stable product in the presence of excess oxidizing agent is acetic acid [t2][t6]. Other options like citric, folic, and malic acids are complex organic acids not produced by the simple oxidation of ethanol.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Formation of coal and petroleum > p. 71