CHEMISTRY

Chemistry



Chemistry

SECTION A: Write one letter corresponding to the most appropriate answer

Q1: B

Q2: C

Q3: E

Q4: A

Q5: E

Q6: D

Q7: E

Q8: A

Q9: B

Q10: C

Section B

Q 11: Structural Formula:

2-methylbutane

2, 2-dimethylpropane

hex-2-ene

dichloromethane

3-hydroxypentan-2-one

1, 2-dibromopropan-2-ol

Q 12:

3-bromobutanol

Citric acid monohydrate

Propanal

3-Bromobutyric acid

Isoleucine

Q 13:

Name and give structural formula of the product of the reaction of the alkene with:-

Alkaline potassium permanganate

Hydrogen bromide

Chlorine

Q 14: Limewater (calcium hydroxide solution) (Irritant) Refer to CLEAPSS Hazcard 18 and Recipe card 15Silver nitrate solution (Low hazard at concentration used) Refer to CLEAPSS Hazcard 87 and Recipe card 58Barium chloride solution (Harmful) Refer to CLEAPSS Hazcard 10A and Recipe Card 7Magneson reagent (Low Hazard at concentration used) Refer to CLEAPSS Recipe card 38Concentrated hydrochloric acid (Corrosive) Refer to CLEAPSS Hazcard 47A and Recipe card 35Hydrochloric acid, 2 mol dm-3(Irritant) See CLEAPSS references aboveNitric acid (Corrosive at concentration used) Refer to CLEAPSS Hazcard 67 and Recipe card 44

1 If the real sea water is not available, it can be made up as shown on the CLEAPSS Recipe card 72.

2 Vacuum filtration apparatus: Buchner funnel and flask, filter paper, access to a vacuum pump - see CLEAPSS Laboratory handbook sections 13.7.7, 10.6.4 and 10.6.5.

3 If students are doing the analysis, flame tests can be carried out by leaving a wooden splint to soak in a mixture of the solid and hydrochloric acid for a few minutes and then placing the splint in a non-luminous Bunsen flame.

Q 14: Preparation of Methyl Iodide from Methyl Alcohol and Phosphorus Iodide

In a 200 cc. round-bottomed flask place 15 grams of methyl alcohol and 3.2 grams of red phosphorus. Have ready a reflux condenser with cork attached. Place the flask in cold water and add in small portions at a time 38 grams of iodine; the addition should take about 10 minutes. If the contents of the flask begin to boil, attach it to the reflux condenser; when reaction ceases add more iodine. Finally attach the flask to the condenser and let it stand for at least 4 hours (preferably over night). Distil through a condenser from a water-bath, as long as any liquid passes over. The receiver should be placed in cold water as methyl iodide is very volatile. Wash the distillate by decantation with a dilute aqueous solution of sodium hydroxide until the lower layer is colourless, and then once with water. Separate the methyl iodide carefully from the water using a separatory funnel, and transfer it to a small distilling flask. Add about 10 grams of anhydrous calcium chloride. Stopper the flask, place a cork over the end of the side-arm, and set aside until the liquid is quite clear. Place a thermometer in the flask, connect the latter with a condenser, and distil from a water-bath. Note the boiling-point and weight of the methyl iodide. Calculate the theoretical yield from the iodine used (why iodine?), and the percentage of this obtained.Methyl iodide boils at 44°, and has the specific gravity 2.27 at 15°. The yield in the experiment should be about 80 per cent of the ...