# What is the reaction between NaOH and urea?

In this video it is mentioned that urea and sodium hydroxide will react to produce ammonia. However, I can't seem to find a clear explanation of the reaction and the other products generated.

One explanation I found says that the NaOH causes the urea to hydrolyze, yielding sodium carbamate, which will then further hydrolyze to sodium carbonate.

Another says that the urea tautomerizes to ammonium cyanate, which preforms a substitution with the NaOH to yield ammonium hydroxide and sodium cyanate.

Which of the two reactions occurs? Do they both occur? Neither?

For urea to tautomerise to ammonium cyanate, a significant rearrangement and breaking a $\ce{C-N}$ bond would be required. Neither is likely in any way.
Well, in practice adding sodium hydroxide granules to a concentrated urea solution at room temperature results in the rapid growth of needle crystals, most likely urea being pushed out of solution. Further heating does not result in $\ce{NH4+}$ or $\ce{NH3}$. However the melting of the dry reactants might produce a different result.