Recent questions in JEEMAIN PAST PAPERS

A straight line through the point $A (3, 4)$ is such that its intercept between the axes is bisected at $A$ . Its equation is :

asked Nov 13, 2018 by pady_1

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The locus of the vertices of the family of parabolas $y = \frac{a^3 x^2}{3} + \frac{a^2x}{2} - 2a$ is :

asked Nov 13, 2018 by pady_1

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In an ellipse, the distances between its foci is 6 and minor axis is 8. Then its eccentricity is :

asked Nov 13, 2018 by pady_1

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$\begin{align} \int^{-\pi/2}_{-3\pi/2} [(x+\pi)^3 + \cos^2 (x+3\pi)] dx \end{align}$ is equal to :

asked Nov 13, 2018 by pady_1

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Suppose a population a has 100 observations 101, 102, ..., 200 and another population $B$ has 100 observations 151, 152, ...., 250. If $V_A$ and $V_B$ represent the variances of the two population respectively, then $\frac{V_A}{V_B}$ is :

asked Nov 13, 2018 by pady_1

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ABC is triangle, right angled at A. The resultant of the force acting along $\overrightarrow{AB}, \overrightarrow{AC}$ with magnitudes $\frac{1}{AB}$ and $\frac{1}{AC}$ respectively is the force along $\overrightarrow{AD}$ , where $D$ is the foot of the perpendicular from $A$ onto $BC$ . The magnitude of the resultant is :

asked Nov 13, 2018 by pady_1

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All the values of m for which both roots of the equation $x^2 - 2mx + m^2 -1 = 0$ are greater than $-2$ but less than 4 lie in the interval :

asked Nov 13, 2018 by pady_1

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Any three vectors such that $\overrightarrow{a}. \overrightarrow{b} \neq 0,\;\overrightarrow{b}. \overrightarrow{c} \neq 0$ , then $\overrightarrow{a}$ and $\overrightarrow{c}$ are :

asked Nov 13, 2018 by pady_1

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The value of $\displaystyle\sum_{k=1}^{10} (\sin \frac{2k \pi}{11} + i \cos \frac{2k \pi}{11})$ is :

asked Nov 13, 2018 by pady_1

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If A and B are square matrices of size $n \times n$ such that $A^2 - B^2 = (A-B) (A+B)$ , then which of the following will be always true ?

asked Nov 13, 2018 by pady_1

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The number of values of $x$ in the interval $[0, 3 \pi]$ satisfying the equation $2 \sin^2x + 5 \sin x - 3 = 0$ is :

asked Nov 13, 2018 by pady_1

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Let $W$ denote the words in the English dictionary. Define the relation R by : $R = \{(x,y) \in W \times W|$ the words $x$ and $y$ have at least one letter in common $\}$ . Then $R$ is :

asked Nov 13, 2018 by pady_1

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The value of the integral $\begin{align} \int_3^6 \frac{\sqrt{x}}{\sqrt{9 - x } + \sqrt{x}} dx \end{align}$

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If the roots of the quadratic equation $x^2 + px + q = 0$ are tan $\tan 30^{\circ}$ and $\tan 15^{\circ}$ respectively, then the value of $2 + q - p$ is :

asked Nov 13, 2018 by pady_1

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$(\Delta H - \Delta U)$ for the formation of carbon monoxide (CO) from its elements at 298 K is : $(R = 8.314 \; JK^{-1} mol^{-1})$

asked Nov 13, 2018 by pady_1

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18 g of glucose $(C_6H_{12} O_6)$ is added to 178.2 g of water. The vapour pressure of water for this aqueous solution at $100^{\circ}C$ is :

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The electrophile involved in the above reaction is :

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How many EDTA (ethylenediaminetetra acetic acid ) molecules are required to make an octahedral complex with a $Ca^{2+}$ ion ?

asked Nov 13, 2018 by pady_1

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The enthalpy changes for the following processes are listed below : $Cl_2 (g) = 2Cl (g), \; \; \; 242.3 \; kJ\; mol^{-1}$ $I_2 (g) = 2I (g), \; \; \; 151.0 \; kJ\; mol^{-1}$ $ICl (g) = I (g) + Cl(g), \; \; \; 211.3 \; kJ\; mol^{-1}$ $I_2 (s) = I_2 (g), \; \; \; 62.76 \; kJ\; mol^{-1}$ Given that the standard states for iodine and chlorine are $I_2 (s)$ and $Cl_2 (g)$ , the standard enthalpy of formation of $ICl \; (g)$ is :

asked Nov 13, 2018 by pady_1

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Density of a $2.05 \; M$ solution of acetic acid in water is $1.02\; g/mL$ . The molality of the solution is :

asked Nov 13, 2018 by pady_1

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The ionic mobility of alkali metal ions in aqueous solution is maximum for :

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Resistance of a conductivity cell filled with a solution of an electrolyte of concentration $0.1\; M$ is $100\; \Omega$ . The conductivity of this solution is $1.29\; S\; m^{-1}$ . Resistance of the same cell when filled with $0.2\; M$ of the same solution is $520 \Omega$ . The molar conductivity of $0.02 \; M$ solution of the electrolyte will be :

asked Nov 13, 2018 by pady_1

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Lanthanide contraction is caused due to :

asked Nov 13, 2018 by pady_1

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The following mechanism has been proposed for the reaction of $NO$ with $Br_2$ to form $NOBr$ : $NO(g) + Br_2 (g) \rightleftharpoons NOBr_2 (g)$ $NOBr_2 (g) + NO (g) \to 2NOBr (g)$ If the second step is the rate determining step, the order of the reaction with respect to $NO (g)$ is :

asked Nov 13, 2018 by pady_1

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Given the data at $25^{\circ}C$ , $Ag + I^- \to AgI + e^- ;\; \; \; E^{\circ} = 0.152 \;V$ $\;\;\;\;\;\;Ag \to Ag^+ + e^-; \; \; \; E^{\circ} = -0.800 \; V$ What is the value of $\log K_{sp}$ for $AgI$ ? $(2.303 \frac{RT}{F} = 0.059\;V)$

asked Nov 13, 2018 by pady_1

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Following statements regardinng the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture ?

asked Nov 13, 2018 by pady_1

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The equilibrium constant for the reaction $SO_3 (g) \rightleftharpoons SO_2(g) + \frac{1}{2} O_2 (g)$ is $K_c = 4.9 \times 10^{-2}$ . The value of $K_c$ for the reaction $2SO_2 (g) + O_2(g) \leftrightharpoons 2SO_3 (g)$ will be :

asked Nov 13, 2018 by pady_1

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The 'spin-only' magnetic moment [ in units of Bohr magneton, ( $\mu_{\beta}$ ) ] of $Ni^{2+}$ in aqueous solution would be (Atomic number of Ni = 28) :

asked Nov 13, 2018 by pady_1

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The alkene formed as a major product in the above elimination reaction is :

asked Nov 13, 2018 by pady_1

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The decreasing values of bond angles from $NH_3 (107^{\circ})$ to $SbH_3 (91^{\circ})$ down group 15 of the periodic table is due to :

asked Nov 13, 2018 by pady_1

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The structure of the compound that gives a tribromo derivative on treatment with bromine water is :

asked Nov 13, 2018 by pady_1

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Increasing order of stability among the three main conformations (i.e., Eclipse, Anti, Gauche) of 2-fluoroethanol is :

asked Nov 13, 2018 by pady_1

1 answer

Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces :

asked Nov 13, 2018 by pady_1

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The structure of the major product formed in the following reaction is :

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Rate of a reaction can be expressed by Arrhenius equation as : $k = Ae^{-E/RT}$ In this equation, $E$ represents :

asked Nov 13, 2018 by pady_1

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In Langmuir's model of adsorption of a gas on a solid surface :

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An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If $T_i$ is the initial temperature and $T_f$ is the final temperature, which of the following statements is correct ?

asked Nov 13, 2018 by pady_1

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The increasing order of the first ionization enthalpies of the elements $B, \; P\; S$ and $F$ (lowest first) is :

asked Nov 13, 2018 by pady_1

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In $Fe(CO)s$ , the $Fe-C$ bond possesses :

asked Nov 13, 2018 by pady_1

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Nickel ( Z = 28 ) combines with a uninegative monodentate ligand $X^-$ to form a paramagnetic complex $[NiX_4]^{2-}$ . The number of unpaired electron(s) in the nickel and geometry of this complex ion are respectively :

asked Nov 13, 2018 by pady_1

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What products are expected from the disproportion reaction of hypochlorous acid ?

asked Nov 13, 2018 by pady_1

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In which of the following molecules / ions all the bonds are not equal ?

asked Nov 13, 2018 by pady_1

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The correct order of increasing acid strength of the compounds : (A) $CH_2CO_2H$ (B) $MeOCH_2CO_2H$ (C) $CF_3CO_2H$ (D) is :

asked Nov 13, 2018 by pady_1

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Which one of the following sets of ions represents a collection of isoelectronic species ?

asked Nov 13, 2018 by pady_1

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The molar conductivities $\bigwedge^{\circ} NaOAc$ and $\bigwedge^{\circ} HCl$ at infinite dilution in water at $25^{\circ}C$ are $91.0$ and $426.2\; S\; cm^2/mol$ respectively. To calculate $\bigwedge^{\circ} HOAc$ , the additional value required is :

asked Nov 13, 2018 by pady_1

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Which of the following statement is true ?

asked Nov 13, 2018 by pady_1

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A metal, M forms chlorides in its $+2$ and $+4$ oxidation states. Which of the following statements about these chlorides is correct ?

asked Nov 13, 2018 by pady_1

1 answer

Fluorobenzene $(C_6H_5F)$ can be synthesized in the laboratory :

asked Nov 13, 2018 by pady_1

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Among the following mixtures, dipole - dipole as the major interaction, is present in :

asked Nov 13, 2018 by pady_1

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The standard enthalpy of formation $(\Delta H_f^{\circ})$ at 298 K for methane, $CH_4 (g)$ , is $-74.8 \; kJ\;mol^{-1}$ . The additional information required to determine the average energy for $C-H$ bond formation would be :

asked Nov 13, 2018 by pady_1

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