How many grams of nitrobenzene must be taken in the reaction to obtain 186 g of anilig.

How many grams of nitrobenzene must be taken in the reaction to obtain 186 g of anilig. If the recovery product yield is 75% of the theoretical.

According to the condition of the problem, we compose the equation:
X g -? m = 186 g. W = 75%
1. C6H5NO2 + 3H2 = C6H5NH2 + 2H2O – reduction of nitrobenzene, obtained aniline;
M (C6H5NH2) = 123 g / mol;
M (C6H5NH2) = 93 g / mol.
2. Calculation of the theoretical mass for aniline, taking into account the product yield:
W = m (practical) / m (theoretical) * 100;
m (C6H5NH2) = 186 / 0.75 = 248 g.
3. Find the number of moles of the reaction product:
Y (C6H5NH2) = m / M = 248/93 = 2.6 mol;
Y (C6H5NO2) = 2.6 mol since the amount of these substances according to the equation is 1 mol.
4. We make calculations of the mass of the initial substance:
m (C6H5NO2) = Y * M = 2.6 * 123 = 319.8 g.
Answer: for recovery, nitrobenzene weighing 319.8 g is required.