CHM 191 TMA SOLUTIONS continuation

 

Q43 The equation NaOH + HCl $$→$$NaCl + H2O is a ____?
 Acid base reaction
 Oxidation reaction
 Neutralization reaction
 Reduction reaction

Q44 When performing acid-base titration, one should first?
 Rinse the burette twice with acid solution
 Fill the burette twice with acid solution
 Fill the burette twice with base solution
 Rinse the burette twice with base solution

Q45 Which of these is a method of finding the equivalence point?
 PH indicator
 Amperometry
 Thermometric titrametry
 All of the above

Q46 What is a titrant in titration analysis?
 Unknown concentration and volume of an analyte
 Known concentration and volume of an analyte
 Partially unknown concentration and volume of acid
 Partially known concentration and volume of an analyte

Q47 What is a titrand in titration analysis?
 Known concentration of an analyte
 Partially known concentration of an analyte
 Partially unknown concentration of acid
 Unknown concentration of an analyte

Q48 During acid-base titration sulphuric acid would be dissociated into what ions?
 $$H{^+} + SO{_4}$$
 $$H{^-} + SO{_4}{^-}$$
 $$2H{^+} + SO{_4}{^-}$$
 $$H{_2} + SO{_4}$$

Q49 Both molarity and normality are measures of concentration. True or false?
 True
 Partially true
 false
 Indifferent

Q50 Choose the most suitable water for use in acid base titration?
 Distilled water
 Deionised water
 Temporary hard water
 Permanent hard water

Q51 A student used a hard tap water and performed and acid base titration. In few lines explain what would happen to his result?
 The starting solution would be more acidic as such it would consume more base to achieve the equivalence point
 the student cannot get an equivalence point owing to the fact that tap water was used not distilled water
 The solution would require more of indicator at the beginning of the experiment
 the starting solution would be more alkaline therefore it would require more volume of acid than expected

Q52 A 25 ml solution of 0.5 M NaOH is titrated until neutralized into a 50 ml sample of HCl?
 50 mol
 0.125 mol
 0.25 mol
 0.5 mol

Q53 What is the importance of back titration?
 To determine the concentration of a substance that is in excess after a chemical reaction.
 To determine the base in excess.
 To determine the acid in excess.
 To determine the average value of acid base titration.

Q54 What is the implication of adding a phenolphthalein as an indicator during the titration of HCl against Na2CO3?
 The end point will appear when only half of Na2CO3 has been used
 The end point will appear at the first drop of the acid.
 The end point will appear when half of the HCl has been used.
 The indicator will be sensitive to the acid alone

Q55 Which of these indicators will be suitable for use in titration involving a weak acid and a strong base?
 Any indicator
 Phenolphthalein
 Methyl orange
 No suitable indicator

Q56 What type of indicator will be suitable for use in a titration involving H2SO4 + NH3(ag)?
 Phenolphthalein
 Methyl orange
 Any indicator
 No suitable indicator

Q57 An example of a strong acid is?
 $$H{_2}SO{_3}$$
 $$CH{_3}COOH$$
 $$H{_2}C{_2}O{_4}$$
 $$H{_2}SO{_4}$$

Q58 What is a strong acid?
 Any acid that ionizes completely in solution
 Any acid which turns blue litmus paper red
 Any acid that is highly corrosive and can cause burn to the skin
 Any acid whose pH is less than 3

Q59 An indicator X was added to an acid solution in a beaker but no colour change was observed give the name of the indicator X?
 Methyl orange
 Bromothymol
 Phenolphthalein
 Litmus paper

Q60 What is the colour of bromothymol when added to an acid solution?
 Blue
 Red
 Yellow
 Colourless

Q61 The unit µg is equivalent to?
 $$10{^-3}$$ Kg
 $$10{^-6}$$ Kg
 $$10{^-12}$$ Kg
 $$10{^-9}$$ Kg

Q62 When filtration is carried out under reduced pressure is called?
 Pressure filtration
 Simple filtration
 Ordinary filtration
 Suction filtration

Q63 The unit of a volume express in $$dm{^3}$$ is equivalent to?
 1 litre or 100 ml
 $$10{^3}$$ cm or 1 litre
 100 $$cm{^3}$$ or 1 litre
 1000 ml or 10 litre

Q64 Define precipitation in respect to wet chemical analysis?
 A method of converting ions in solution into an insoluble compound
 The process of separating solid (crystals or precipitate) from the liquid (mother liquor)
 A method of reducing the volume of by heating
 A method of converting water vapour in to liquid water

Q65 What is a mole?
 The amount of substance which contains as many element as there are atoms in 12 g carbon 12
 The amount of substance which is contain in a solution
 The amount of substance equivalent to carbon 12 atom present in a solution
 All the options are correct

Q66 Why do we heat precipitates during gravimetric analysis?
 To obtain a compound of constant composition
 To increase the solubility of the precipitates
 To dry the precipitates
 To speed the reaction rate of the precipitates

Q67 The Avogadro number $$6.02 X 10{^23}$$ is equivalent to?
 Number of atoms, ions or molecules in a mole
 Number of mole of an atom equivalent to carbon atom
 Number of elementary units in a mole of a substance
 All options above are correct

Q68 Choose from the list of chemicals given and determine which has negative effect on skin?
 Tetraoxosulphate(VI)and hydrogensulphide
 Esters and ethanols
 Benzene and benzoylchloride
 Phenols and hydrogenfloride

Q69 Calculate the molar mass of 1 mole of a pure substance weighting X g?
 M=2X g $$mol{^-1}$$
 M=1/X g $$mol{^-1}$$
 M=X g $$mol{^-1}$$
 M=1 g $$mol{^-1}$$

Q70 Which of these hazardous chemicals are likely to cause dizziness and are carcinogenic?
 Ethanol
 benzene
 Silvernitrate
 Phenol

Q71 Calculate the mass of 0.5 moles of water?
 9.408 g
 18.016 g
 18.071 g
 4.504 g

Q72 The hazardous effect of chlorinated alkanes is?
 Highly oxidizing
 irritant
 Skin burns
 Causes mental confusion

Q73 Calculate the number of moles in 24 g of oxygen gas?
 281 mol
 265 mol
 7.8 mol
 3.8 mol

Q74 All are laboratory safety tips except?
 Wearing lab coat or apron
 Close all windows and doors
 Never work alone in the laboratory
 Be familiar with the position of some safety equipment

Q75 Calculate the molar mass of a pure substance if 2 moles of the substance has a mass of 35 g?
 17.5 $$g mol{^-1}$$
 70 g $$mol{^-1}$$
 35 g $$mol{^-1}$$
 37 g $$mol{^-1}$$

Q76 Qualitative analysis helps in determining what in a given solution?
 How long it will take for reactant to react to form products
 How much of a component is present in that solution
 The quantity of the solvent required to form solution with the component
 What type of component is present in that solution

Q77 Define molality of a solution?
 Weight in grams of a substance per formula weight in kilograms of that substance
 The number of moles of solute per $$dm{^3}$$ of a solution
 The number of moles of solute in one kilogram of solution
 Moles of solute per volume of solution express in litre

Q78 Quantitative methods help in determining what in a solution?
 How much of a component is present in the solution
 What type of component is present in a solution
 The quantity of a solvent required to form a solution with the component
 How long will take for reactant to react in order to form products

Q79 Normality can be defined as?
 Moles of solute in 1 $$dm{^3}$$ of solution
 Weight in gram of a substance per formula weight in kilo gram of substance
 Number of gram equivalent weight of a solute in one litre of solution
 All the options are correct

Q80 The various method of quantitative analysis include?
 Acid –base titration and Oxidative analysis
 Gravimetric, spectrophotometric and volumetric methods
 Titration, Gravimetric, and Volumetric
 Spectrophotometric, Oxidative and Neutralization methods