A metal (A) on heating in nitrogen gas gives compound B.
Question: A metal (A) on heating in nitrogen gas gives compound B. B on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a dark blue-violet coloured solution. A and B respectively, are :$\mathrm{Mg}$ and $\mathrm{Mg}_{3} \mathrm{~N}_{2}$$\mathrm{Na}$ and $\mathrm{NaNO}_{3}$$\mathrm{Mg}$ and $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$$\mathrm{Na}$ and $\mathrm{Na}_{3} \mathrm{~N}$Correct Option: 1 Solution:...
Read More →The major product [B]
Question: The major product $[\mathrm{B}]$ in the following sequence of reactions is :- Correct Option: 1 Solution:...
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Question: The number of $\mathrm{sp}^{2}$ hybridised carbons present in "Aspartame" is Solution:...
Read More →The flucculation value of
Question: The flucculation value of $\mathrm{HCl}$ for arsenic sulphide sol. is $30 \mathrm{~m}$ mole $\mathrm{L}^{-1}$. If $\mathrm{H}_{2} \mathrm{SO}_{4}$ is used for the flocculation of arsenic sulphide, the amount, in grams, of $\mathrm{H}_{2} \mathrm{SO}_{4}$ in $250 \mathrm{ml}$ required for the above purpose is (molecular mass of $\mathrm{H}_{2} \mathrm{SO}_{4}=98 \mathrm{~g} / \mathrm{mol}$ ) Solution:...
Read More →Kjeldahl's method cannot be used to estimate
Question: Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?(1) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}$$\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$$\mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{N}$Correct Option: 1 Solution: Kjeldahl's method for estimation of nitrogen is not applicable for nitrobenzene $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}$. because reaction with $\mathrm{H}_{2} \mathrm{SO}_{4}$, nitrobenzene can not give ...
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Question: The standard heat of formation $\left(\Delta_{f} \mathrm{H}_{298}^{0}\right)$ of ethane in $(\mathrm{kJ} / \mathrm{mol})$, if the heat of combustion of ethane, hydrogen and graphite are $-1560$, $-393.5$ and $-286 \mathrm{~kJ} / \mathrm{mol}$, respectively is Solution: $2 \mathrm{C}($ graphite $)+3 \mathrm{H}_{2}(\mathrm{~g}) \longrightarrow \mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{~g})$ $\Delta_{\mathrm{f}} \mathrm{H}\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)=2 \Delta \mathrm{H}_{\text {...
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Question: $3 \mathrm{~g}$ of acetic acid is added to $250 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{HCl}$ and the solution made up to $500 \mathrm{~mL}$. To $20 \mathrm{~mL}$ of this solution $\frac{1}{2} \mathrm{~mL}$ of $5 \mathrm{M} \mathrm{NaOH}$ is added. The $\mathrm{pH}$ of the solution is [Given : $\mathrm{pK}_{\mathrm{a}}$ of acetic acid $=4.75$, molar mass of acetic acid $=60 \mathrm{~g} / \mathrm{mol}, \log 3=0.4771$ ] Neglect any changes in volume Solution:...
Read More →Conside the following reactions :
Question: Conside the following reactions : $\mathrm{NaCl}+\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}+\mathrm{H}_{2} \mathrm{SO}_{4}$ (Conc.) $\rightarrow$ (A) $+$ Side products (A) $+\mathrm{NaOH} \rightarrow$ (B) $+$ Side product (B) $+\mathrm{H}_{2} \mathrm{SO}_{4}$ (dilute $)+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow$ (C) $+$ Side product The sum of the total number of atoms in one molecule each of (A), (B) and (C) is Solution:...
Read More →The increasing order of the atomic radii
Question: The increasing order of the atomic radii of the following elements is :- (a) $\mathrm{C}$ (b) $\mathrm{O}$ (c) $\mathrm{F}$ (d) $\mathrm{Cl}$ (e) $\mathrm{Br}$$(\mathrm{b})(\mathrm{c})(\mathrm{d})(\mathrm{a})(\mathrm{e})$$(\mathrm{a})(\mathrm{b})(\mathrm{c})(\mathrm{d})$ (e)$(\mathrm{d})(\mathrm{c})$ (b) $$ (a) $$ (e)$(\mathrm{c})$ (b) $$ (a) $$ (d) $$ (e)Correct Option: , 4 Solution:...
Read More →An unsaturated hydrocarbon X
Question: An unsaturated hydrocarbon $X$ absorbs two hydrogen molecules on catalytic hydrogenattion, and also gives following reaction : $\mathrm{B}(3$ - oxo - hexanedicarboxylic acid $)$ $\mathrm{X}$ will be :-Correct Option: 1 Solution:...
Read More →For the reaction
Question: For the reaction $2 \mathrm{H}_{2}(\mathrm{~g})+2 \mathrm{NO}(\mathrm{g}) \rightarrow \mathrm{N}_{2}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$ the observed rate expression is, rate $=\mathrm{k}_{\mathrm{f}}[\mathrm{NO}]^{2}\left[\mathrm{H}_{2}\right]$. The rate expression of the reverse reaction is : $\mathrm{k}_{\mathrm{b}}\left[\mathrm{N}_{2}\right]\left[\mathrm{H}_{2} \mathrm{O}\right]^{2} /[\mathrm{NO}]$$\mathrm{k}_{\mathrm{b}}\left[\mathrm{N}_{2}\right]\left[\mathrm{H}...
Read More →Consider the following plots of rate constant versus
Question: Consider the following plots of rate constant versus $\frac{1}{T}$ for four different reactions. Which of the following orders is correct for the activation energies of these reactions? $\mathrm{E}_{\mathrm{b}}\mathrm{E}_{\mathrm{d}}\mathrm{E}_{\mathrm{c}}\mathrm{E}_{\mathrm{a}}$$\mathrm{E}_{\mathrm{a}}\mathrm{E}_{\mathrm{c}}\mathrm{E}_{\mathrm{d}}\mathrm{E}_{\mathrm{b}}$$\mathrm{E}_{\mathrm{c}}\mathrm{E}_{\mathrm{a}}\mathrm{E}_{\mathrm{d}}\mathrm{E}_{\mathrm{b}}$$\mathrm{E}_{\mathrm{b...
Read More →Among the compounds A and B
Question: Among the compounds $A$ and $B$ with molecular formula $\mathrm{C}_{9} \mathrm{H}_{18} \mathrm{O}_{3}, \mathrm{~A}$ is having higher boiling point the B. The possible structures of $A$ and $B$ are : Correct Option: 1 Solution: Alcohol has more boiling point than ether (due to hydrogen bonding). $\mathrm{So}$,...
Read More →Among the reactions (a) - (d),
Question: Among the reactions (a) - (d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are : (a) $\mathrm{CaO}+\mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3}$ (b) $3 \mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{CO} \rightarrow 2 \mathrm{Fe}_{3} \mathrm{O}_{4}+\mathrm{CO}_{2}$ (c) $\mathrm{FeO}+\mathrm{SiO}_{2} \rightarrow \mathrm{FeSiO}_{3}$ (d) $\mathrm{FeO} \rightarrow \mathrm{Fe}+\frac{1}{2} \mathrm{O}_{2}$(c) and (d)(a) and (d)(d)(a)Correct Option: 1...
Read More →In the following reaction squence, structures of
Question: In the following reaction squence, structures of $\mathrm{A}$ and $\mathrm{B}$, respectively will be: Correct Option: , 4 Solution:...
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Question: A river $400 \mathrm{~m}$ wide is flowing at a rate of $2.0 \mathrm{~m} / \mathrm{s}$. A boat is sailing at a velocity of $10 \mathrm{~m} / \mathrm{s}$ with respect to the water, in a direction perpendicular to the river. (a) Find the time taken by the boat to reach the opposite bank. (b) How far from the point directly opposite to the starting point does the boat reach the opposite bank? Solution: (a) Velocity responsible for crossing is $10 \mathrm{~m} / \mathrm{s}$ $=\frac{\text { d...
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Question: One man is sitting on the shores of a river. He is in the line of $1.0 \mathrm{~m}$ long boat and is $5.5 \mathrm{~m}$ away from the center of the boat. If he can throw the apply only with a speed of $10 \mathrm{~m} / \mathrm{s}$. find the minimum and maximum angles of projection for successful shot. Assume that the point of projection and the edge pf the boat are in the same horizontal level. Solution: For near point of boat $R=5 m=\frac{u^{2} \sin 2 \theta}{g} g$ $5=\frac{(10)^{2} \s...
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Question: The benches of a gallery in a cricket stadium are $1 \mathrm{~m}$ wide and $1 \mathrm{~m}$ high. A batsman strikes the ball at a level one metre above the ground and hits a mammoth sixer. The ball starts at $35 \mathrm{~m} / \mathrm{s}$ at an angle of $53^{\circ}$ with the horizontal. The benches are perpendicular to the place of motion and the first bench is $110 \mathrm{~m}$ from the batsman on which bench hwill the ball hit? Solution: Let ball lands on the nth bench $\therefore \mat...
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Question: A person is standing on a truck moving with a constant velocity of $14.7 \mathrm{~m} / \mathrm{s}$ on a horizontal road. The man throws a ball in such a way that it returns to the truck after the truck has moved $58.8 \mathrm{~m}$. Find the speed and the angle of projection (a) as seen from the truck, (b) as seen from the road. Solution: Time taken by ball=Time taken by truck to cover $58.8 \mathrm{~m}$ Time= $\frac{\underline{\text { distance }}}{\text { speed }}=\frac{58.8}{14.7}=4 \...
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Question: A staircase contains three steps each $10 \mathrm{~cm}$ high and $20 \mathrm{~cm}$ wide as shown in figure. What should be the minimum horizontal velocity of a hall rolling off the uppermost plane so as to hit directly the lowest plane? Solution: For minimum velocity ball will just be touching point $B$ If $A$ is origin then coordinates of $B(40,-20)$ $\mathrm{Y}=\mathrm{x} \tan \theta-\frac{1}{2} \frac{\mathrm{x}^{2}}{\mathrm{~g}^{\mathrm{u}^{2} \cos ^{2} \theta}}$ $-20=40 \tan 0^{\ci...
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Question: A boy is standing on a long railroad car throws a ball straight upwards. The car is moving on the horizontal road with an acceleration of $1 \mathrm{~m} / \mathrm{s}^{2}$ and the projection velocity in the vertical direction is $9.8$ $\mathrm{m} / \mathrm{s}$. How far behind the boy will the ball fall on the car? Solution: $\underline{2 u \sin \theta}$ Time of flight for ball $=$ g $=\frac{2(9.8) \sin 9 \overline{0}^{-}}{\text {E }}$ $t=2 \sec$ For ball-car, along horizontal direction ...
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Question: A bomb is dropped from a plane flying horizontally with uniform speed, Show that the bomb will explode vertically below the plane. Is the statement true if the plane flies with uniform speed but not horizontally? Solution: During release, $\mathrm{u}_{\text {plane }}=\mathrm{U}_{\text {bomb }}$ Along x-axis, $\mathrm{u}_{\mathrm{rel}}=0$ $\mathrm{a}_{\mathrm{rel}}=0$ So, at any time, $\mathrm{s}_{\mathrm{rel}}=0$ So, bomb will always be below and will explode If plane is at some angle ...
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Question: Find the average velocity of a projectile between the instants it crosses half the maximum height. It is projected with a speed $u$ at an angle $\theta$ with the horizontal Solution: Let particle reaches from $A$ to $B$ in time t. By symmetry, $A B$ line is horizontal So, displacement $A B=u_{x} t$ Velocity $=\stackrel{\text { displacement }}{\text { time }}=\frac{\text { uxt }}{t}$ $\mathrm{V}_{\mathrm{avg}}=\mathrm{u} \cos \theta$...
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Question: A ball is projected from a point on the floor with a speed of $12 \mathrm{~m} / \mathrm{s}$ at an angle 60 with the horizontal, Will it hit a vertical wall $5 \mathrm{~m}$ away from the point of projection and perpendicular to the plane of projection without hitting the floor? Will the answer differ if the wall is $22 m$ away? Solution: $R=\frac{u^{2} \sin 2 \theta}{g}$ $=\frac{(15)^{2} \sin (2 x 60)}{9.8}$ $\mathrm{R}=19.88 \mathrm{~m}$ Ball will hit $5 \mathrm{~m}$ away wall If wall ...
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Question: A person standing on top of a cliff $171 \mathrm{ft}$ high has to throw a packet to his friend standing on the ground $228 \mathrm{ft}$ horizontally away. If he throws the packet directly aiming at the friend with a speed of $15.0 \mathrm{ft} / \mathrm{s}$, how short will the packet fall? Solution: $\operatorname{Tan} \theta=228 / 171=4 / 3$ $\theta=53^{\circ}$ $x$-axis $y$-axis $u_{x}=15 \sin 53 u_{y}=15 \cos 53$ $u_{x}=12 \mathrm{ft} / \mathrm{sec} \mathrm{u}_{\mathrm{y}}=9 \mathrm{f...
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