In an aqueous solution containing sodium bicarbonate, aniline reacts quickly with bromine to give 2,4,6-tribromoaniline. nitration of aniline requires very strong conditions, however, and the yields (mostly m-nitroaniline) are poor.

-

In bromination of aniline, due to the strongly activating NH2 group 2,4,6-tribromoaniline is formed.

In nitration of aniline the reagent used is concentrated nitric acid. Nitric acid reacts with aniline Nitrogen and protonates it. Due to NH3+ group formation, the benzene ring becomes strongly deactive in the ortho and para positions.

Hence the yields towards nitro nucleophile is poor.

The meta position being more electron rich than ortho or para due to the strongly deactivating group hence yields m-nitroaniline.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.