Mixed Practice

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Showing 2551 to 2575 of 3046 questions (page 103 of 122).

2551. The element with the highest electronegativity is

A. caesium B. chlorine C. nitrogen D. fluorine E. oxygen

2552. Metallic character generally

A. is highest for noble gases B. increases down a group C. decreases down a group D. is unrelated to position E. increases across a period

2553. The screening or shielding effect of inner electrons

A. decreases the effective nuclear charge felt by outer electrons B. has no effect on atomic size C. increases ionization energy D. only applies to d electrons E. increases the effective nuclear charge

2554. The number of elements in the fourth period of the periodic table is

A. 2 B. 8 C. 10 D. 32 E. 18

2555. Alkali metals are stored under kerosene oil because they

A. dissolve in water slowly B. are radioactive C. react vigorously with air and moisture D. are volatile E. sublime readily

2556. Among the alkali metals, lithium has the highest

A. atomic number B. density C. ionization energy D. atomic radius E. reactivity with water

2557. The chemical formula of gypsum is

A. CaSO4.2H2O B. CaCO3 C. CaO D. CaSO4 E. CaSO4.(1/2)H2O

2558. Sodium carbonate is used industrially mainly in the manufacture of

A. cement B. petrol C. plastics D. glass E. fertilizer

2559. Carbon monoxide is highly toxic because it

A. dissolves in water B. is acidic C. reacts with nitrogen D. decomposes in the lungs E. binds strongly to haemoglobin in place of oxygen

2560. The catalyst used in the contact process for manufacturing sulphuric acid is

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

2561. Silicon carbide is used as an abrasive because it is

A. metallic B. highly ionic C. a covalent network solid of great hardness D. a soft molecular solid E. volatile

2562. Concentrated nitric acid acts on copper mainly as

A. a dehydrating agent B. a base C. a reducing agent D. an oxidizing agent E. a catalyst

2563. The bleaching action of chlorine water is due to

A. chlorine gas dissolving the dye B. hydrogen gas C. reduction of the dye D. hydrochloric acid E. nascent oxygen from hypochlorous acid

2564. The oxidation state of chromium in the dichromate ion is

A. +6 B. +2 C. +4 D. +7 E. +3

2565. Paramagnetism in transition metal compounds is due to

A. the nucleus B. lattice vibrations C. delocalized pi bonds D. unpaired d electrons E. paired electrons

2566. Stainless steel is an alloy of iron with

A. lead and zinc B. carbon only C. chromium and nickel D. copper and tin E. aluminium and silicon

2567. In acidic medium, permanganate ion is reduced to

A. MnO4 2- B. Mn2+ C. Mn3+ D. MnO2 E. Mn metal

2568. Successive members of a homologous series differ by

A. CH3 B. C2H4 C. CH4 D. H2 E. CH2

2569. The number of structural isomers of butane, C4H10, is

A. 2 B. 4 C. 5 D. 3 E. 1

2570. The Wurtz reaction is used to prepare

A. alkynes from dihalides B. symmetrical alkanes from alkyl halides C. alcohols from esters D. ketones from acids E. alkenes from alcohols

2571. Dehydration of ethanol with concentrated sulphuric acid gives

A. ethanoic acid B. ethyne C. ethene D. ethane E. ethanal

2572. Baeyer's reagent, dilute alkaline potassium permanganate, is used to test for

A. alcohols B. aldehydes C. unsaturation in hydrocarbons D. carboxylic acids E. amines

2573. Ethyne is prepared in the laboratory by the action of water on

A. calcium carbonate B. calcium chloride C. calcium oxide D. calcium carbide E. calcium sulphate

2574. The catalyst used in Friedel Crafts alkylation of benzene is

A. nickel B. vanadium pentoxide C. sodium hydroxide D. concentrated sulphuric acid E. anhydrous aluminium chloride

2575. The nitrating mixture used for the nitration of benzene consists of

A. ammonium nitrate and water B. concentrated nitric and concentrated sulphuric acids C. nitrous acid and ethanol D. nitric acid and sodium hydroxide E. dilute nitric acid alone

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