Vertical columns on the periodic table are known as and horizontal rows are called
O periods, groups
groups, periods
O metals, nonmetals
O metalloids, metals

Maximum theoretical percent recovery of acetanilide is 86.8%

Explanation:

From the given information:

Solubility of acetanilide in 100 ml water at 100 C = 5.5 g

Solubility of acetanilide in 100 ml water at 0 C = 0.53 g

When 4.0 g of acetanilide is dissolved in 100 ml of water, all of it will go into solution. As the solution is cooled to 0 C only 0.53 g of it will dissolve.

Amount of acetanilide undissolved =