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#QuestionSubject and topicDifficulty
51 What are the usual units of the rate of a reaction in solution? Chemistry
Rate of reaction		 Easy
52 How is the instantaneous rate of a reaction found from a graph of reactant concentration against time? Chemistry
Rate of reaction		 Easy
53 In 2N₂O₅ → 4NO₂ + O₂, N₂O₅ disappears at 0.02 mol L⁻¹ s⁻¹. At what rate is NO₂ formed? Chemistry
Rate of reaction		 Medium
54 For 2HI(g) → H₂(g) + I₂(g), which expression correctly gives the rate of reaction? Chemistry
Rate of reaction		 Medium
55 Why does powdered marble react faster with dilute HCl than a single lump of the same mass? Chemistry
Rate of reaction		 Hard
56 Which statement about molecularity is correct? Chemistry
Rate law, order and molecularity		 Easy
57 The rate constant of a reaction has units of s⁻¹. What is the order of the reaction? Chemistry
Rate law, order and molecularity		 Easy
58 For 2NO + O₂ → 2NO₂, rate = k[NO]²[O₂]. By what factor does the rate change if [NO] is doubled while [O₂] is … Chemistry
Rate law, order and molecularity		 Medium
59 For a reaction A + B → products, doubling [A] alone doubles the rate, while doubling [B] alone has no effect … Chemistry
Rate law, order and molecularity		 Medium
60 For CHCl₃ + Cl₂ → CCl₄ + HCl, rate = k[CHCl₃][Cl₂]^½. What are the units of k? Chemistry
Rate law, order and molecularity		 Hard
61 The half-life of a first-order reaction is 10 minutes. What is its rate constant? Chemistry
Integrated rate equations		 Easy
62 For which order of reaction is the half-life independent of the initial concentration? Chemistry
Integrated rate equations		 Easy
63 How many half-lives are needed for 75% of a first-order reaction to be completed? Chemistry
Integrated rate equations		 Medium
64 A zero-order reaction has [R]₀ = 0.2 mol L⁻¹ and k = 0.01 mol L⁻¹ s⁻¹. What is its half-life? Chemistry
Integrated rate equations		 Medium
65 The acid-catalysed hydrolysis of ethyl acetate behaves as a first-order reaction even though it involves este… Chemistry
Integrated rate equations		 Hard
66 How does a catalyst increase the rate of a reaction? Chemistry
Temperature and rate		 Easy
67 In the Arrhenius equation k = A e^(−Ea/RT), what does the factor e^(−Ea/RT) represent? Chemistry
Temperature and rate		 Easy
68 A plot of ln k against 1/T for a reaction is a straight line. What is its slope? Chemistry
Temperature and rate		 Medium
69 According to collision theory, why do many collisions with enough energy still fail to give products? Chemistry
Temperature and rate		 Medium
70 The rate constant of a reaction doubles when the temperature rises from 300 K to 310 K. What is the approxima… Chemistry
Temperature and rate		 Hard
71 What is the ground-state outer electronic configuration of chromium (Z = 24)? Chemistry
Transition elements: general properties		 Easy
72 Why is zinc not regarded as a typical transition element? Chemistry
Transition elements: general properties		 Easy
73 Which 3d transition element shows the largest number of oxidation states? Chemistry
Transition elements: general properties		 Medium
74 Why does copper not liberate hydrogen gas from dilute hydrochloric acid? Chemistry
Transition elements: general properties		 Medium
75 Which ion would you expect to act as a strong reducing agent in aqueous solution? Chemistry
Transition elements: general properties		 Hard
76 Which ion is colourless in aqueous solution? Chemistry
Properties of transition metals		 Easy
77 Which catalyst is used in the contact process for making sulphuric acid? Chemistry
Properties of transition metals		 Easy
78 What is the spin-only magnetic moment of Mn²⁺ (Z of Mn = 25)? Chemistry
Properties of transition metals		 Medium
79 An ion of a 3d metal has a spin-only magnetic moment of 3.87 BM. How many unpaired electrons does it have? Chemistry
Properties of transition metals		 Medium
80 Which property is NOT typical of interstitial compounds of transition metals? Chemistry
Properties of transition metals		 Hard
81 What colour change is seen when acidified potassium dichromate acts as an oxidising agent? Chemistry
Oxides, oxoanions and important compounds		 Easy
82 Which ore is the starting material for the manufacture of potassium dichromate? Chemistry
Oxides, oxoanions and important compounds		 Easy
83 How many electrons are gained per permanganate ion when it acts as an oxidising agent in acidic solution? Chemistry
Oxides, oxoanions and important compounds		 Medium
84 What happens when an acid is added to a yellow solution of potassium chromate? Chemistry
Oxides, oxoanions and important compounds		 Medium
85 Why is hydrochloric acid not used to acidify KMnO₄ in redox titrations? Chemistry
Oxides, oxoanions and important compounds		 Hard
86 What is the most common oxidation state of the lanthanoids? Chemistry
Lanthanoids and actinoids		 Easy
87 What is the main cause of lanthanoid contraction? Chemistry
Lanthanoids and actinoids		 Easy
88 Why do zirconium and hafnium have almost identical atomic radii? Chemistry
Lanthanoids and actinoids		 Medium
89 Which lanthanoid ion is a good oxidising agent in aqueous solution? Chemistry
Lanthanoids and actinoids		 Medium
90 Why do actinoids show a wider range of oxidation states than lanthanoids? Chemistry
Lanthanoids and actinoids		 Hard
91 Which metal catalyst is used in the Haber process for ammonia? Chemistry
Applications of d- and f-block elements		 Easy
92 Which compound is widely used in photographic films because it is sensitive to light? Chemistry
Applications of d- and f-block elements		 Easy
93 Misch metal, used in lighter flints, mainly consists of: Chemistry
Applications of d- and f-block elements		 Medium
94 Which catalyst combination is used to polymerise ethene in the Ziegler process? Chemistry
Applications of d- and f-block elements		 Medium
95 A factory converts vegetable oils into solid fats by hydrogenation. Which catalyst is most likely used? Chemistry
Applications of d- and f-block elements		 Hard
96 What is the coordination number of the metal in [Co(en)₃]³⁺? Chemistry
Werner’s theory and key terms		 Easy
97 What is the oxidation state of iron in K₄[Fe(CN)₆]? Chemistry
Werner’s theory and key terms		 Easy
98 Which ligand is ambidentate? Chemistry
Werner’s theory and key terms		 Medium
99 One mole of CoCl₃·5NH₃ is treated with excess AgNO₃ solution. How many moles of AgCl are precipitated? Chemistry
Werner’s theory and key terms		 Medium
100 Which is a heteroleptic complex? Chemistry
Werner’s theory and key terms		 Hard