Recent questions in Chemistry

Choose the correct option below based on the following statement:

asked Dec 17, 2013 by sreemathi.v

1 answer

Which of following are necessary for successful collisions to occur? </br> (i) Favourable collision geometry </br> (ii) sufficient kinetic energy </br> (iii) Large $\Delta H$ </br>

asked Dec 17, 2013 by sreemathi.v

1 answer

The photochemical reactions are those which

asked Dec 17, 2013 by sreemathi.v

1 answer

Consider the following reaction : $NaOH(aq)+HCl(aq)\rightarrow H_2O(l)+NaCl(aq)$ .The rate of reaction can be found by observing change in concentration

asked Dec 17, 2013 by sreemathi.v

1 answer

Consider the statement: Solid Mg added to 2M HCl. In the first 10 seconds,the temperature of container increased by $1^0C$ and 20ml of $H_2$ was produced. Determine rate of reaction.

asked Dec 17, 2013 by sreemathi.v

1 answer

In the following reaction and graph: $2H_2O_2(l)\rightarrow 2H_2O_2+O_2(g)$ , he average rate of reaction is greatest in which time period?

asked Dec 17, 2013 by sreemathi.v

1 answer

Consider the following reaction; $2H_2O_2(l)\rightarrow 2H_2O(l)+O_2(g)$ which graph shows the relation between rate of consumption of $H_2O_2$ and time?

asked Dec 17, 2013 by sreemathi.v

1 answer

The rate of chemical equation is equal to slope of graph with ones labelled

asked Dec 17, 2013 by sreemathi.v

1 answer

Ammonia can be oxidized by oxygen to produce $NO_2$ according to reaction $4NH_3+7O_2\rightarrow 4NO_2+6H_2O$ .If water is formed of $36\;mol\;L^{-1}min^{-1}$ .Then respective rates of $NH_3,O_2$ used will be(in M/min)

asked Dec 17, 2013 by sreemathi.v

1 answer

For the reaction $A\;\;\;\underrightarrow{k_1}\;\;\;B\;\;\;\underrightarrow{k_2}\;\;\;C$ , select the correct statement:

asked Dec 17, 2013 by sreemathi.v

1 answer

A first order reaction is 50% completed in 45 minute at $87^oC$ and in 9minutes at $127^oC$ .The energy of activation of the reaction is

asked Dec 17, 2013 by sreemathi.v

1 answer

The rate constant $k_1\: and \: k_2$ for two different reactions are $106{16}.e^{-2000/T}\: and \: 10^{15}.e^{-1000/T}$ , respectively. The temperature at which $k_1 = k_2$ is :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

For the gas phase reaction, $PCI_5(g) \leftrightharpoons PCI_3(g) +CI_2 (g)$ which of the following conditions are correct ?

asked Dec 16, 2013 by thanvigandhi_1

0 answers

If the concentration of $OH^-$ ions in the reaction $Fe(OH)_3 (s) \leftrightharpoons Fe^{3+}(aq)+3\: OH^-(aq)$ is decreased by $\large\frac{1}{4}$ times, then equilibrium concentration of $Fe^{3+}$ will increase by :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

$Kp_1\: and \: Kp_2$ for the reactions $X \leftrightharpoons Y+Z.............(1) \: and \: A \leftrightharpoons 2B ............(2)$ are in the ratio of 9 : 1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (1) and (2) are in the ratio :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the $H^+$ ion concentration in the mixture ?

asked Dec 16, 2013 by thanvigandhi_1

1 answer

Which of the following statements is not correct ?

asked Dec 16, 2013 by thanvigandhi_1

0 answers

Bond dissociation enthalpy of $H_2,CI_2\: and \: HCI$ are 434, 242 and 431 $kJmol^{-1}$ respectively. Enthalpy of formation of HCI is :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

What volume of oxygen gas ( $O_2$ ) measured at $0^{\circ}C$ and 1 atm, is needed to burn completely 1L of propane gas $(C_3H_8)$ measured under the same conditions?

asked Dec 16, 2013 by thanvigandhi_1

0 answers

The bromination of acetone that occurs in acid solution is represented by this equation $CH_3COCH_3(aq)+Br_2(aq) \rightarrow CH_3COCH_2Br(aq) +H^+(aq)+Br^-(aq)$

asked Dec 16, 2013 by thanvigandhi_1

0 answers

The measurement of the electron position is associated with an uncertainty in momentum, which is equal to $1 \times 10^{-18} g\: cm\: s^{-1}$ . The uncertainty in electron velocity is, ( mass of an electron is $9 \times 10^{-28}g)$

asked Dec 16, 2013 by thanvigandhi_1

0 answers

Which of the following are not state functions ?

asked Dec 16, 2013 by thanvigandhi_1

0 answers

Kohlrausch's law states that at :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

If 'a' stands for the edge length of the cubic systems : simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these systems will be respectively

asked Dec 16, 2013 by thanvigandhi_1

1 answer

The decomposition of $N_2O_5$ is a first order reaction represented by $N_2O_5\rightarrow N_2O_4+\large\frac{1}{2}$ $O_2$ .After 15minutes the volume of $O_2$ produced is 9ml & at the end of the reaction 35ml.The rate constant is equal to

asked Dec 16, 2013 by sreemathi.v

1 answer

The value of equilibrium constant of the reaction $HI (g) \rightleftharpoons \large\frac{1}{2} H_2(g) + \large\frac{1}{2} I_2$ is 8.0. The equilibrium constant of the reaction $H_2(g) +I_2(g) \rightleftharpoons 2HI(g)$ will be :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

What is the unit of k of a $n^{th}$ order reaction?

asked Dec 16, 2013 by sreemathi.v

1 answer

If a gas expands at constant temperature, it indicates that,

asked Dec 16, 2013 by thanvigandhi_1

0 answers

If uncertainty in position and momentum are equal, then uncertainty in velocity is :

asked Dec 16, 2013 by thanvigandhi_1

0 answers

What is the rate of the reaction $A+B\rightarrow C$ based on the following experiments:

asked Dec 16, 2013 by sreemathi.v

1 answer

If a reaction is catalyzed by $x$ , then $x$

asked Dec 16, 2013 by sreemathi.v

1 answer

The catalyst increases the rate of reaction because it

asked Dec 16, 2013 by sreemathi.v

1 answer

For the parallel reactions depicted below, which of the following options are correct?

asked Dec 16, 2013 by sreemathi.v

1 answer

For the given sequential reaction $A\;\underrightarrow{k_1}\;B\;\underrightarrow {k_2}C$ the concentration of A,B & C at any time 't' is given by $[A]_t=[A]_oe^{-k_1t};[B]_t=\large\frac{k_1[A_o]}{k_2-k_1}$ $[e^{-k_1t}-e^{-k_2t}];[C]_t=[A_o]-([A]_t-([A]_t+[B]_t)$ .The time at which a concentration of B is maximum is

asked Dec 16, 2013 by sreemathi.v

1 answer

For the given sequential reaction $A\;\overset{k_1} \rightarrow \;B\;\overset{k_2} \rightarrow C$ the concentration of A,B & C at any time 't' is given by $[A]_t=[A]_oe^{-k_1t};[B]_t=\large\frac{k_1[A_o]}{k_2-k_1}$ $[e^{-k_1t}-e^{-k_2t}];[C]_t=[A_o]-([A]_t-([A]_t+[B]_t)$ .The maximum concentration of $[B]$ is

asked Dec 16, 2013 by sreemathi.v

1 answer

For a first order reaction $A\rightarrow 2B$ ,graph for $\large\frac{d[B]}{dt}$ vs $\large\frac{-d[A]}{dt}$ is

asked Dec 16, 2013 by sreemathi.v

1 answer

Consider the following first order completing reactions : $X\;\overset{k_1}{\longrightarrow}\;A+B$ and $Y\;\overset{k_2}{\longrightarrow}\;C+D$ if $50\%$ of the reaction of $X$ was completed when $87.5\%$ of the reaction of $Y$ was completed , the ratio of their constants $(k_1/k_2)$ is

asked Dec 16, 2013 by sreemathi.v

1 answer

For the reaction $A\rightarrow B$ the rate law expression $-\large\frac{d[A]}{dt}$ $=k[A]^{1/2}$ .Select the correct statement:

asked Dec 16, 2013 by sreemathi.v

1 answer

For the reaction $A\rightarrow B$ ,the rate law expression is $-\large\frac{d[A]}{dt}$ $=k[A]^{3/2}$ . If the initial concentration of $A$ is $[A]_0$ , which of the following is true?

asked Dec 16, 2013 by sreemathi.v

1 answer

For reaction $C+D\rightarrow A+B$ ,the rate expression is rate= $k[C]^{1/2}[D]^{1/2}$ starting with initial concentration of 4M of C and D each,what is time taken for concentration of A to become 0.25M.Given : $k=2.303\times 10^{-2}sec^{-1}$

asked Dec 16, 2013 by sreemathi.v

1 answer

For first order decomposition reaction, $A(g)\rightarrow B(g)$ rate of formation of B against time t will be:

asked Dec 16, 2013 by sreemathi.v

1 answer

Select the correct statement:

asked Dec 16, 2013 by sreemathi.v

1 answer

Which of the following is correct expression for an irreversible nth order reaction?

asked Dec 16, 2013 by sreemathi.v

1 answer

Given the following parallel reactions, where $\large\frac{k_1}{k_2}=\frac{1}{3}$ . Initially only 4 moles of A are present. The total number of moles of C at the end of 50% reaction is:

asked Dec 16, 2013 by sreemathi.v

1 answer

Given the following parallel reactions, where $\large\frac{k_1}{k_2}=\frac{1}{3}$ . Initially only 4 moles of A are present. The total number of moles of A,B & C at the end of 50% reaction is:

asked Dec 16, 2013 by sreemathi.v

1 answer

Rate of reaction can be expressed by Arrhenius equation as $k=Ae^{\large\frac{-E_a}{RT}}$ .Select the correct statement

asked Dec 16, 2013 by sreemathi.v

1 answer

The rate law for a reaction $A\rightarrow B$ is rate= $K[A]^m[B]^n$ .On tripling the concentration of A and halving the concentration of B,the ratio of new rate to the earlier rate of the reaction will be as

asked Dec 16, 2013 by sreemathi.v

1 answer

The rate constant for a first order reaction is $20hr^{-1}$ .The half life of the reaction will be

asked Dec 16, 2013 by sreemathi.v

1 answer

In a first order reaction,the concentration of the reactant decreases from 0.02M to 0.005M in 10min.The time taken to change the concentration of reactant from 0.16M to 0.025M

asked Dec 16, 2013 by sreemathi.v

1 answer

Adsorption is accompanied by

asked Dec 14, 2013 by mosymeow_1

1 answer

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