The correct order of increasing acidity among the given compounds is:

CH3COOK < CH2COONa < CH3-COO-CH2-CH2 < CH2COOH

Explanation:

CH3COOK is the least acidic as it is the conjugate base of acetic acid (CH3COOH) and is a weaker acid than the other compounds.CH2COONa is the next least acidic as it is the conjugate base of sodium acetate (CH3COONa), which is a stronger acid than acetic acid.CH3-COO-CH2-CH2 is more acidic than the previous compounds as the presence of an extra methylene group increases the acidity of the carboxylic acid.CH2COOH is the most acidic as it is acetic acid, which is a stronger acid than the other compounds listed.