Recent questions tagged past papers

A particle is moving with velocity $v = K(y \hat i + x \hat j) $, where K is a constant. The general equation for its path is

asked Dec 11, 2018 by pady_1

0 answers

A ball is made of a material of density $\rho$ where $\rho_{oil} < \rho < \rho_{water}$ with $\rho_{oil}$ and $\rho_{water}$ representing the densities of oil and water, respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position ?

asked Dec 11, 2018 by pady_1

0 answers

Statement-1 : When ultraviolet light is incident on a photocell, its stopping potential is $V_0$ and the maximum kinetic energy of the photoelectrons is $K_{max}$. When the ultraviolet light is replaced by X- rays, both V0 and Kmax increase. Statement-2 : Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light.

asked Dec 11, 2018 by pady_1

0 answers

Statement-1 : Two particles moving in the same direction do not lose all their energy in a completely inelastic collision. Statement-2 : Principle of conservation of momentum holds true for all kinds of collisions.

asked Dec 11, 2018 by pady_1

0 answers

Let C be the capacitance of a capacitor discharging through a resistor R. Suppose $t_1$ is the time taken for the energy stored in the capacitor to reduce to half its initial value and $t_2$ is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio $t_1/t_2$ will be

asked Dec 11, 2018 by pady_1

0 answers

A rectangular loop has a sliding connector PQ of length A and resistance $R \Omega$ and it is moving with a speed v as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents $I_1, I_2$ and I are

asked Dec 11, 2018 by pady_1

0 answers

For a particular reversible reaction at temperature $T, \Delta H$ and $\Delta S$ were found to be both +ve. If Te is the temperature at equilibrium, the reaction would be spontaneous when

asked Dec 11, 2018 by pady_1

0 answers

The polymer containing strong intermolecular forces e.g. hydrogen bonding,

asked Dec 11, 2018 by pady_1

0 answers

The correct order of $E^0_{M^2/M}$ values with negative sign for the four successive elements $Cr,Mn,Fe$

asked Dec 11, 2018 by pady_1

0 answers

Biuret test is not given by

asked Dec 11, 2018 by pady_1

0 answers

Out of the following, the alkene that exhibits optical isomerism is

asked Dec 11, 2018 by pady_1

0 answers

Percentage of free space in cubic close packed structure and in body centred packed structure are respectively

asked Dec 11, 2018 by pady_1

0 answers

At $25^{\circ}C$, the solubility product of $Mg(OH)_2$ is $1.0 \times 10^{–11}$. At which $pH$, will $Mg^{2+}$ ions start precipitating in the form of $Mg(OH)_2$ from a solution of $0.001\; M \;Mg^{2+}$ ions ?

asked Dec 11, 2018 by pady_1

0 answers

The Gibbs energy for the decomposition of $Al_2O_3$ at $500^{\circ}C$ is as follows : $\large\frac{2}{3}$$Al_2O_3 \to \large\frac{4}{3}$$Al+O_2, \Delta_rG=+966\;kJ\;mol^{-1}$ The potential difference needed for electrolytic reduction of $Al_2O_3$ at $500^{\circ}C$ is at least

asked Dec 11, 2018 by pady_1

0 answers

Solubility product of silver bromide is $5.0 \times 10^{–13}$. The quantity of potassium bromide (molar mass taken as $120 \;g \;of\; mol^{–1}$) to be added to $1 \;litre\; of\; 0.05\; M$ solution of silver nitrate to start the precipitation of AgBr is

asked Dec 11, 2018 by pady_1

0 answers

The correct sequence which shows decreasing order of the ionic radii of the elements is

asked Dec 11, 2018 by pady_1

0 answers

The correct order of increasing basicity of the given conjugate bases $(R = CH_3)$ is

asked Dec 11, 2018 by pady_1

0 answers

The edge length of a face centered cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is

asked Dec 11, 2018 by pady_1

0 answers

In aqueous solution the ionization constants for carbonic acid area $K_1=4.2 \times 10^{-}$ and $K_2=4.8 \times 10^{-11}$ Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

asked Dec 11, 2018 by pady_1

0 answers

Three reactions involving $H_2 PO_4^{-}$ are given below :$(i)H_3PO_4+H_2O \to H_3O^{+} +H_2PO_4^{-} \qquad (ii) H_2PO_4^{-}+H_2O \to HPO_4^{2-}+H_3O^{+} \qquad (iii)H_2PO_4^{-}+OH^{-} \to H_3PO_4+O^{2-}$ In which of the above does $H_2PO_4^{-}$ act as an acid ?

asked Dec 11, 2018 by pady_1

0 answers

The main product of the following reaction is $C_6H_5CH_2CH(OH)CH(CH_3)_2 \qquad \underrightarrow{\qquad conc.H_2SO_4 \qquad} \qquad ?$

asked Dec 11, 2018 by pady_1

0 answers

On mixing, heptane and octane form an ideal solution. At $373\; K$, the vapour pressures of the two liquid components (heptane and octane) are $105\; k\;Pa$ and $45\; k\;Pa$ respectively. Vapour pressure of the solution obtained by mixing $25.0\;g$ of heptane and $35\; g$ of octane will be (molar mass of heptane = $100 g\; mol^{–1}$ an dof octane $= 114\; g\; mol^{–1}).$

asked Dec 11, 2018 by pady_1

0 answers

Which one of the following has an optical isomer ?

asked Dec 11, 2018 by pady_1

0 answers

Consider the following bromides : The correct order of $S_N1$0 reactivity is

asked Dec 11, 2018 by pady_1

0 answers

Ionisation energy of $He^{+}$ is $19.6 \times 10^{–18}\; J \;atom^{–1}.$ The energy of the first stationary state $(n = 1)$ of $Li^{2+}$ is

asked Dec 11, 2018 by pady_1

0 answers

The energy required to break one mole of Cl–Cl bonds in $Cl_2$ is $242 \;kJ\; mol^{–1}$. The longest wavelength of light capable of breaking a single $Cl – Cl$ bond is $(c = 3 x 10^8 ms^{–1} \;and\; NA = 6.02 \times 10^{23} mol^{–1})$

asked Dec 11, 2018 by pady_1

0 answers

$29.5\; mg$ of an organic compound containing nitrogen was digested according to Kjeldahl’s method and the evolved ammonia was absorbed in $20\; mL$ of $0.1\; M\; HCl$ solution. The excess of the acid required $15\; mL$ of $0.1\; M \;NaOH$ solution for complete neutralization. The percentage of nitrogen in the compound is

asked Dec 11, 2018 by pady_1

0 answers

In the chemical reactions, the compounds ‘A’ and ‘B’ respectively are

asked Dec 11, 2018 by pady_1

0 answers

From amongst the following alcohols the one that would react fastest with conc. $HCl$ and anhydrous $ZnCl_2$, is

asked Dec 11, 2018 by pady_1

0 answers

If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water ($\Delta T_f$), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is $(K_f = 1.86\; K\; kg\; mol^{–1})$

asked Dec 11, 2018 by pady_1

0 answers

One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of $44\; u$. The alkene is

asked Dec 11, 2018 by pady_1

0 answers

If $10^{–4 }dm^3$ of water is introduced into a $1.0\; dm^{3}$ flask to 300 K, how many moles of water are in the vapour phase when equilibrium is established ? (Given : Vapour pressure of $H_2O$ at $300\; K$ is $3170 \;Pa ; R = 8.314 J K^{–1} mol^{–1})$

asked Dec 11, 2018 by pady_1

0 answers

Consider the reaction : $Cl_2(aq) + H_2S(aq) \to S(s) + 2H^{+}(aq) + 2Cl^{–} (aq)$ The rate equation for this reaction is rate $= k [Cl_2] [H_2S]$ Which of these mechanisms is/are consistent with this rate equation ?
 (A) $Cl_2 + H_{2}S \to H^+ + Cl^- + Cl^+ + HS^- \;$ (slow)
$Cl^{+} + HS^{–} \to H^+ + Cl^- + S (fast)$
 $(B)\; H_2S \Leftrightarrow H^+ + HS^- $(fast equilibrium)
$Cl_2 + HS^{–} \to 2Cl^{–} +H^+ + S$ (slow)

asked Dec 11, 2018 by pady_1

0 answers

A solution containing $2.675\; g$ of $CoCl_3. 6 NH_3$ (molar mass =$ 267.5 \;g \;mol^{–1})$ is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $AgNO_3$ to give $4.78\; g$ of $AgCl$ (molar mass $= 143.5\; g \;mol^{–1}$). The formula of the complex is (At. Mass of $Ag = 108 \;u$)

asked Dec 11, 2018 by pady_1

0 answers

The time for half life period of a certain reaction $A \to$ products is 1 hour. When the initial concentration of the reactant ‘A’, is $2.0\; mol\; L^{–1},$ how much time does it take for its concentration to come from $0.50\; to 0.25\; mol\; L^{–1}$ if it is a zero order reaction ?

asked Dec 11, 2018 by pady_1

0 answers

The standard enthalpy of formation of $NH_3$ is $–46.0\; kJ mol^{–1}.$ If the enthalpy of formation of $H_2$ from its atoms is $–436\; kJ mol^{–1}$ and that of $N_2$ is $–712\; kJ mol^{–1},$ the average bond enthalpy of $N–H$ bond in $NH_3$ is

asked Dec 11, 2018 by pady_1

0 answers

Let A be a $2 \times 2$ matrix Statement-1: adj (adj A) = A Statement-2 : |adj A| = |A|

asked Nov 29, 2018 by pady_1

0 answers

Statement -1 : $\sim (p \leftrightarrow \sim q) $ is equivalent to $p \leftrightarrow q$ Statement -2: $\sim (p \leftrightarrow \sim q) $ is a tautology.

asked Nov 29, 2018 by pady_1

0 answers

Statement -1: The variance of first n even natural numbers is $\frac{n^2-1}{4}$ Statement -2 :The sum of first $n$ natural numbers is $\frac{n(n+1)}{2}$ and the sum of squares of first $n$ natural numbers is $\frac{n(n+1)(2n+1)}{6}$

asked Nov 29, 2018 by pady_1

1 answer

Let $f(x) = x|x| $ and $g(x) = \sin x$ Statement -1 : gof is differentiable at $x=0$ and its derivative is continuous at the point. Statement -2 : gof is twice differentiable at $x=0$

asked Nov 29, 2018 by pady_1

0 answers

Let $f(x) = (x+1)^2 - 1, x \geq -1$ Statement -1 : The set $\{ x : f(x) = f^{-1} (x) \} = \{0, -1\}$ Statement-2: f is a bijection.

asked Nov 29, 2018 by pady_1

1 answer

The shortest distance between the line $y - x = 1$ and the curve $x = y^2$ is

asked Nov 29, 2018 by pady_1

0 answers

Given $P(x) = x^4 + ax^3 + bx^2+cx+d$ such that $x=0$ is the only real root of $P'(x) = 0$. If $P(-1) < P(1)$, then in the interval $[-1, 1]$

asked Nov 29, 2018 by pady_1

0 answers

The area of the region bounded by the parabola $(y-2)^2 = x-1$, the tangent to the parabola at the point (2, 3) and the x-axis is

asked Nov 29, 2018 by pady_1

0 answers

Let $y$ be an implicit function of $x$ defined by $x^{2x} - 2x^{x} \cot y -1 =0$. Then $y'(1)$ equals

asked Nov 29, 2018 by pady_1

0 answers

One ticket is selected at random from 50 tickets numbered $00, 01, 02, .....49$. Then the probability that the sum of the digits on the selected ticket is 8, given that the product of these digits is zero, equals

asked Nov 29, 2018 by pady_1

0 answers

The differential equation which represents the family of curves $y = c_1e^{c_2x}$, where $c_1$ and $c_2$ are arbitrary constants is

asked Nov 29, 2018 by pady_1

0 answers

The sum of the infinity of the series $1 + \frac{2}{3} + \frac{6}{3^2} + \frac{10}{3^3}+\frac{14}{3^4} + . . . . $ is

asked Nov 29, 2018 by pady_1

0 answers

The ellipse $x^2+4y^2 = 4$ is inscribed in a rectangle aligned with the coordinate axes, which in turn in inscribed in another ellipse that passes through the point (4, 0). Then the equation of the ellipse is

asked Nov 29, 2018 by pady_1

0 answers

The remainder left out when $8^{2n} - (62)^{2n+1}$ is divided by 9 is

asked Nov 29, 2018 by pady_1

0 answers

Ask Questions, Get Answers