Chemistry - Online Test

Chemical reactions rarely  occur completely when exactly the right amounts of reactants are taken to react together  to yield products as per its stoichiometry .One of the  reactants  will be used up  ,before another runs out.Thus , the reactant which  is consumed first is known as limiting reagent 

For  the given reaction ,

2 N2 H4 (l)      +     N2 O4  (l)  ------>   3 N2 (g)     +  4 H2 O (l)

as per its stoichiometry , if  only the right and exact amount of  N2 O4 is taken , the reaction may not go to completion .As such it would be consumed first & is , therefore , the  limiting reagent. 

Ozonolysis of alkenes involves the addition of ozone molecule to alkene to form an unstable ozonide , and then cleavage of the ozonide by (Zn+H2O) to smaller molecules .  

2- butene is a symmetrical alkene , which on ozonolysis yields two moles of CH3CHO  having molecular mass   of 44 u. as per reaction given   below,