Conjugated dienes react with radicals by both 1,2 and 1,4 addition. Write a detailed mechanism to account for this fact using the hydrogen peroxide-promoted addition of one molar equivalent of HBr to 1,3-butadiene as an illustration.

Liquid from a brewery fermentation contains 10% ethanol and 90% water. part of the fermentation product (50,000 kg/h) is pumped to a distillation column on the factory site. under current operating conditions, a distillate of 45% ethanol and 55% water is produced from the top of the column at a rate of one-tenth that of the feed. what is the composition of the waste "bottoms" from the still?