# How is using Jones reagent different than Potassium dichromate in Sulfuric acid for the oxidation of alcohols?

I was taught at an institution I study in that using $\ce{K2Cr2O7}$ in the presence of $\operatorname{dil}.\ce{H2SO4}$ will oxidise $1^{\circ}$ alcohols to aldehydes, and $2^{\circ}$ alcohols to ketones. This is supported in here too.

At the same time, I came across Jones reagent ($\ce{Na2Cr2O7}$ in the presence of $\operatorname{dil}.\ce{H2SO4}$) on Khan Academy. But this says that it is an extremely strong oxidising agent and can oxidise Aldehydes to Carboxylic Acids too (thus giving acids on the oxidation of $1^{\circ}$ alcohols).

I do not understand how the above two reagents have different oxidising abilities. Is my premise itself wrong or is there any reason for it to have different oxidising abilities?

• Jones Reagent usually oxidises primary alcohols to acids via the aldehyde. Only aldehydes which do not form hydrates (eg benzylic or allylic) are stable to Jones conditions and are not oxidised further. The reagents you refer to are all the same regardless of how they ate prepared. – Waylander Jan 6 '18 at 17:49
• @Waylander So the sources that say in case of Potassium dichromate with Sulfuric acid oxidises primary alcohols to aldehydes are partially correct, and those aldehydes will be oxidised to acids? Please add your comment as an answer. – Siddharth Venu Jan 6 '18 at 18:17