CHM291: Practical Chemistry Iii-inorganic TMA1Question and answer

Question 1 : Which of the following is suitable for drying off water from alcohol?
A. Heating to dryness
B. Options b and c above
C. Anhydrous sodium sulphate
D. Calcium chloride

Answer is C anhydrous sodium sulphate

Question 2 : During recrystallization, the blockage of the filter funnel can be avoided by
A. A further adding a small quantity of solvent
B. None of the above
C. Filtering only hot solution
D. Dissolving the crude solid into the solvent in the normal way

Answer is A. further adding a small quantity of solvent

Question 3 : One of the precaution notes when removing Impurities from crude liquid is�?�.?
A. Reagent should always be used in small quantity
B Choice of the solvent
C. Washing a crude liquid
D. Reagent should always be used in large quantity

Answer is A. Reagent should always be used in small quantity

Question 4 : What should be done to large crystals or lumps?
A. Grind to reduce particle size
B. Estimate the weight in a container
C. Dissolve in solvents to reduce size
D. Heat to melt to reduce size

Answer is A. Grind to reduce particle size

Question 5 : Grease can cause corneal damage. True or false?
A. false
B. undefined
C. Very true
D. Partially true

Answer is C very true

Question 6 : The process of removing colour impurities using charcoal is by�?�?
A. chemisorption
B. dehydration
C. Absorption
D. adsorption

Answer is D adsorption

Question 7 : What is the purpose of distillation?
A. To purify a liquid
B. To purify a solid
C. To isolate a pure compound
D To add solvent to a solution

Answer is A to purify a liquid

Question 8 : What should be done if crystallization is slow to start?
A. Further lowering of temperature
B. Swirling the flask
C. scratching inside of the flask
D. Increase the pressure

Answer is C Scratching inside of the flask

Question 9 : Seizure can be avoided when we disassemble the apparatus immediately after used. True or false?
A. true
B. false
C. Not applicable
D. undefined

Answer is A true

Question 10 : To speed the drying of a sample we need �?�.?
A. desiccator
B. Ovum chamber
C. Simple desiccator
D. Vacuum desiccator

Answer is A desiccator

Question 11 : Open flask method of crystallization is fast but has what limitation?
A. It is only carried out directly on the hot plate
B. The solvent is only allowed to come to a boil and then the flask is removed from the heat
C. Highly precaution need to be applied or face risk of fire
D. The method is not suitable for low boiling solvent

Answer is D. The method is not suitable for low boiling solvent

Question 12 : Indicate the suitable condenser to be used when the solvent is volatile and the reaction mixture has to be kept boiling for long time
A. Reflux condenser
B. Water condenser
C. All of the above
D. Air condenser

Answer is A Reflux condenser

Question 13 : The purpose of fractional distillation is to �?�.?
A. To separate the two liquid of different boiling point
B. None of the above
C. To separate to liquid of different vaporization point
D. To separate two solid of different melting point

Answer is A to separate the two liquid of different boiling point

Question 14 : Which separation technique is suitable for separating two immiscible liquids
A. distillation
B. Use of separating funnel
C. decantation
D. precipitation

Answer is B use of separating funnel

Question 15 : The common cause of seizure of a glass joint is?
A. Large lump of crystals
B. Caustic soda
C. Sulphuric acid
D. Caustic alkali

Answer is D caustic alkali

Question 16 : Desiccator is good for drying many solids except�?��?�?
A. Inorganic solids
B. hydrates
C. Organic solids
D. Brittle solids

Answer is B hydrate

Question 17 : Which of the statements base define charcoal?
A. An amorphous carbon form from the incomplete combustion of animal or vegetable matter
B. Charcoal is a fossil fuel
C. Charcoal is a purifying agent
D. Charcoal is an energy source for cooking

Answer is A. An amorphous carbon form from the incomplete combustion of animal or vegetable matter

Question 18 : In the laboratory, damp solids are drained using�?�?
A. Crucible
B. Filter paper
C. desiccator
D. Ovum chamber

Answer is B. Filter paper
Question 19 : The method of air drying is safe in all solid except in �?�?
A. Deliquescence solid
B. Small quantity of solid
C. Large quantity of solid
D. Deliquescence liquid

Answer is A. Deliquescence solid

Question 20 : The following are examples of alternative method of loosening a seized glass joint except..?
A. Warm the joint in a small flame, then tap gently
B. Tap the joint gently
C. Rock the cone in the socket
D. Lubricate the joint with grease then tap gently

Answer is D. Lubricate the joint with grease then tap gently