What happens in this reaction and why? 3-methylbutane-1,3-diol + cro3 -->

Here we have to explain and get the product of the reaction between 3-methyl-1,3-diol and chromium-tri-oxide (CrO₃)

The reaction between 3-methyl-1,3-diol with chromium-tri-oxide (CrO₃) form 3-methyl-3-hydroxybutanal.

The CrO₃ is used as a mild oxidant to the alcohol. It only produces aldehyde or ketone depending upon the position of the -OH group in a secondary or primary alcohol.

Here we can see there are two hydroxy (-OH) group in the reactant. However one of the hydroxy is at terminal carbon atom, thus primary alcohol and other in between as tertiary alcohol.

As the reagent CrO₃ does not reacts on the tertiary -OH group thus the -OH group present at 3 position will not be oxidized. Thus only the terminal hydroxy group will oxidize to form the corresponding aldehyde.

Henceforth the final product of the reaction is 3-methyl-3-hydroxybutanal as shown in the figure.  

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

your parents i think this could be it