Carbohydrates and Vitamines

Which statements must be true for a compound to be classed as a monosaccharide?

I. It must possess at least one hydroxyl group.

II. It must have the general formula (CH2O)n.

III. It must contain a carbonyl group.

• I, II and III

• II and III only

• I and III only

• I and II only

Which is both an aldose and a pentose?

• 
• 
• 
• 

Carbohydrates provide a quick and convenient source of energy. The reaction can be summarized as complete combustion in oxygen to give carbon dioxide and water.

Which is the general equation for the combustion of any monosaccharide or polysaccharide?

• C_x(H₂O)y + (x + y/2)O₂ → xCO₂ + yH₂O

• (CH₂O)n + nO₂ → nCO₂ + nH₂O

• C_x(H₂O)y + xO₂ → xCO₂ + yH₂O

• (CH₂O)n + (n + n/2)O₂ → nCO₂ + nH₂O

Which two molecules are formed when one molecule of sucrose is hydrolysed in acid solution?

• 
• 
• 
• 

What name is given to the bond formed when two monosaccharides condense together to form a disaccharide and water?

• coordinate bond

• peptide bond

• hydrogen bond

• glycosidic bond

Which functional groups are present in vitamin A

I. alkenyl

II. hydroxyl

III. phenyl

• I and II only

• I, II and III

• II and III only

• I and III only

Which vitamin helps to regulate the amount of calcium and phosphate in the human body?

• vitamin A

• vitamin B6

• vitamin C

• vitamin D

In the past sailors on long sea voyages used to suffer from 'scurvy'. What was the cause of this disease?

• lack of fresh fruit and vegetables

• eating too much fish

• drinking contaminated water

• exposure to too much sunlight

Which vitamins are fat-soluble?

• I and II only

• I and III only

• II and III only

• I, II and III

The molar mass of vitamin C is 176 g mol⁻¹. The percentage of vitamin C in a vitamin tablet can be determined by titration with iodine solution.

C₆H₈O₆(aq) + I₂(aq) → C₆H₆O₆(aq) + 2H⁺(aq) + 2I⁻(aq)

It requires 20.0 cm³ of 0.100 mol dm⁻³ iodine solution to react exactly with a solution made by dissolving a vitamin tablet with a mass of 1.00 g in 100.0 cm³ of water.

What is the percentage of vitamin C in the tablet? Assume nothing else in the tablet reacts with iodine.

• 17.6%

• 1.76%

• 35.2%

• 3.52%