21. Write structure, in line or condensed notation, for the major product(s) of the following reactions (include stereochemistry where appropriate): Os04NaHSO3, H20NaNH3H20H2SO4Hg(OAc)21. 032. (CH3)2S NaOCH(CH3)2(CH3)2CHOH50°cBrHCH3NaN3DMFBr25°сBr2H20ОНH2SO4heat

Alkene gives a hydroxylation reaction with osmium tetraoxide. In this reaction, two hydroxy groups attached to the carbon atoms that are attached with a double bond.The reaction is a stereospecific reaction and proceeds by a concerted mechanism and the syn addition of the hydroxy group takes place. The reaction is given below:Reduction of alkyne: The alkyne is reduced into trans alkene when they react with sodium in liquid ammonia. The reaction proceeds by the free radical reaction mechanism and the radical intermediate is formed in this reaction.Hydration of alkyne: Alkyne gives hydration reactions in presence of an H2SO4 and HgSO4 catalyst. In this reaction, a water molecule adds to the triple bond to form a carbonyl compound. A hydroxyl group (OH−) attaches to one carbon of the triple bond, and a proton (H+) adds to the other carbon of the triple bond. In this reaction a weak pi-bond of alkene replaced by two strong sigma bonds, hence the reaction is highly exothermic. The reaction completes in two steps. In the first step, a proton adds to the alkyne to form a more stable carbocation. In the second step H2O molecule bonds to the carbocation. The reaction follows the Markovnikov rule. The oxygen atom at this point has three bonds and carries a positive. Another water molecule comes along and takes up the extra proton.Please note: According to the guideline in one session only three parts of a question can be solved. Ask the remaining part of the question in a separate session. Do not forget to mention the subpart that you want to solve.