Mixed Practice

Free set

Showing 1951 to 1975 of 3046 questions (page 79 of 122).

1951. A cell placed in a hypertonic solution will

A. shrink as water leaves it B. swell and burst C. gain solute rapidly D. remain unchanged E. divide

1952. Rusting of iron requires the presence of

A. water only B. both oxygen and water C. nitrogen D. carbon dioxide only E. oxygen only

1953. Galvanizing protects iron because zinc

A. is less reactive than iron B. forms an ionic bond with iron C. is a better conductor D. prevents the entry of nitrogen only E. is more reactive and corrodes preferentially as a sacrificial metal

1954. During electroplating, the article to be plated is made the

A. cathode B. salt bridge C. reference electrode D. electrolyte E. anode

1955. According to Faraday's first law, the mass of a substance deposited during electrolysis is proportional to

A. the electrode area B. the temperature C. the resistance of the cell D. the quantity of charge passed E. the voltage applied

1956. The standard reduction potential of the zinc electrode is about

A. 0.00 V B. +0.76 V C. +0.34 V D. -0.34 V E. -0.76 V

1957. The usual unit of reaction rate is

A. mol dm-3 s-1 B. dm3 mol-1 C. mol dm-3 D. s-1 E. mol s

1958. According to collision theory, a collision leads to reaction only if the molecules have sufficient energy and

A. equal masses B. a catalyst present C. identical speeds D. the same charge E. the correct orientation

1959. A reaction initiated by the absorption of light is called

A. an electrochemical reaction B. a chain terminating reaction C. a photochemical reaction D. a thermal reaction E. an autocatalytic reaction

1960. For a main group element, the number of valence electrons is indicated by its

A. atomic mass B. oxidation state only C. group number D. atomic radius E. period number

1961. The second ionization energy of an element is always greater than the first because

A. the nuclear charge decreases B. the electron is closer to the nucleus in the neutral atom C. the atom becomes larger D. shielding increases E. an electron is removed from a positively charged ion

1962. Across a period, the character of the oxides changes from

A. acidic to neutral only B. basic to neutral only C. unchanged D. basic through amphoteric to acidic E. acidic through amphoteric to basic

1963. The transition elements occupy the

A. p block B. d block C. s block D. noble gas group E. f block

1964. The chemical inertness of the noble gases is due to their

A. completely filled valence shells B. radioactivity C. large size D. high density E. low atomic mass

1965. The hydrides of the alkali metals are

A. polymeric B. ionic solids containing the hydride ion C. metallic D. covalent and volatile E. non-existent

1966. Permanent hardness of water is caused mainly by dissolved

A. calcium and magnesium sulphates and chlorides B. potassium nitrate C. calcium and magnesium bicarbonates D. dissolved carbon dioxide E. sodium chloride

1967. Caustic soda is the common name for

A. sodium carbonate B. sodium chloride C. sodium bicarbonate D. sodium hydroxide E. calcium hydroxide

1968. Graphite conducts electricity because

A. it contains free protons B. it is amorphous C. each carbon has one delocalized electron in a layer structure D. it has ionic bonds E. its atoms are sp3 hybridized

1969. Ammonia is manufactured industrially by the

A. contact process B. Haber process C. Solvay process D. Bosch process E. Ostwald process

1970. Sulphur dioxide acts as a bleaching agent by

A. reduction B. precipitation C. oxidation D. adsorption only E. hydrolysis

1971. Anhydrous copper sulphate is white while the pentahydrate is blue because the colour arises from

A. water molecules coordinated to the copper ion B. the sulphate ion C. the crystal shape D. impurities E. hydrogen bonding alone

1972. The catalyst used in a vehicle catalytic converter is mainly

A. vanadium pentoxide B. nickel C. platinum and rhodium D. iron E. aluminium chloride

1973. In naming a complex ion, the ligands are cited

A. after the metal B. in order of charge only C. only if they are anionic D. before the metal in alphabetical order E. at random

1974. Geometrical isomerism in alkenes arises because of

A. free rotation about the double bond B. restricted rotation about the double bond C. hydrogen bonding D. resonance E. the presence of a chiral centre

1975. Optical isomerism requires the presence of

A. an aromatic ring B. a lone pair C. a carbon atom bonded to four different groups D. a hydrogen bond E. a double bond

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