PYQ Vault
EbooksTutor

Rate of formation or disappearance of one species from another's, using stoichiometry

This type of question, asked 5 times: 2021 Paper 20, 25 Jun 2022, 11 Apr 2023, 30 Jan 2024, 23 Jan 2026 S2. All 5 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    2021 Paper 20

    52
    The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is 2 K2Cr2O7+8H2SO4+3C2H6O→2Cr2(SO4)3+2{\text{ }K}_{2}Cr_{2}O_{7}+ 8H_{2}SO_{4}+ 3C_{2}H_{6}O \rightarrow 2Cr_{2}\left( SO_{4} \right)_{3}+ 3C2H4O2+2 K2SO4+11H2O3C_{2}H_{4}O_{2}+ 2{\text{ }K}_{2}SO_{4}+ 11H_{2}O If the rate of appearance of Cr2(SO4)3Cr_{2}\left( SO_{4} \right)_{3} is 2.67 mol2.67\text{ }mol min⁡−1\min^{- 1} at a particular time, the rate of disappearance of C2H6OC_{2}H_{6}O at the same time is ____\_\_\_\_ mol min⁡−1\min^{- 1}. (Nearest integer)

  2. Question 2

    25 Jun 2022

    58
    For a given chemical reaction
    γ1 A+γ2 B→γ3C+γ4D\gamma_{1}\text{ }A +\gamma_{2}\text{ }B \rightarrow\gamma_{3}C +\gamma_{4}D
    Concentration of CC changes from 10mmol10mmol dm−3dm^{- 3} to 20mmoldm −320mmoldm\ ^{- 3} in 10 seconds. Rate of appearance of DD is 1.5 times the rate of disappearance of BB which is twice the rate of disappearance AA. The rate of appearance of DD has been experimentally determined to be 9mmol9mmol dm−3 s−1dm^{- 3}{\text{ }s}^{- 1}. Therefore the rate of reaction is moldm −3 s−1moldm\ ^{- 3}{\text{ }s}^{- 1}. (Nearest Integer)

  3. Question 3

    11 Apr 2023

    58
    KClO3+6FeSO4+3H2SO4→ KCl+3Fe2(SO4)3+3H2OKClO_{3}+ 6FeSO_{4}+ 3H_{2}SO_{4}\rightarrow \ KCl + 3Fe_{2}\left( SO_{4} \right)_{3}+ 3H_{2}O The above reaction was studied at 300 K300\text{ }K by monitoring the concentration of FeSO4FeSO_{4} in which initial concentration was 10M10M and after half an hour became 8.8M8.8M. The rate of production of Fe2(SO4)3Fe_{2}\left( SO_{4} \right)_{3} is___ ×10−6 mol L−1 s−1\times10^{- 6}\text{ }mol{\text{ }L}^{- 1}{\text{ }s}^{- 1}. (Nearest integer)

  4. Question 4

    30 Jan 2024

    142
    NO2NO_{2} required for a reaction is produced by decomposition of N2O5N_{2}O_{5} in CCl4CCl_{4} as by equation 2 N2O5( g)→4NO2( g)+O2( g)2{\text{ }N}_{2}O_{5(\text{ }g)}\rightarrow 4NO_{2(\text{ }g)}+O_{2(\text{ }g)} The initial concentration of N2O5N_{2}O_{5} is 3 mol L−13\text{ }mol{\text{ }L}^{- 1} and it is 2.75 mol L−12.75\text{ }mol{\text{ }L}^{- 1} after 30 minutes. The rate of formation of NO2NO_{2} is x×10−3 mol L−1x \times10^{- 3}\text{ }mol{\text{ }L}^{- 1} min⁡−1\min^{- 1}, value of xx is _______

  5. Question 5

    23 Jan 2026 S2

    36
    Observe the following reactions at T(K)T(K) (I) A → products. (II) 5Br−(aq)+BrO3−(aq)+6H+(aq)→3Br2(aq)+3H2O(l)5{Br}^{-}(aq) + {BrO}_{3}^{-}(aq) + 6H^{+}(aq) \rightarrow 3{Br}_{2}(aq) + 3H_{2}O(l) Both the reactions are started at 10.00 am . The rates of these reactions at 10.10 am are same. The value of −Δ[Br−]Δt-\frac{\Delta\left\lbrack Br^{-} \right\rbrack}{\Delta t} at 10.10 am is 2×10−4 mol L−1Min−12 \times10^{- 4}\text{ }mol{\text{ }L}^{- 1}Min^{- 1}. The concentration of A at 10.10 am is 10−2 mol L−110^{- 2}\text{ }mol{\text{ }L}^{- 1}. What is the first order rate constant (in min⁡−1\min^{- 1} ) of reaction I?

    Tap an option to check your answer.