Cement, the important building material is a mixture
Question: Cement, the important building material is a mixture of oxides of several elements. Besides calcium, iron and sulphur, oxides of elements of which of the group (s) are present in the mixture? (i) group 2 (ii) groups 2, 13 and 14 (iii) groups 2 and 13 (iv) groups 2 and 14 Solution: Option (ii)groups 2, 13 and 14 is the answer...
Read More →Dry ice is
Question: Dry ice is (i) Solid NH3 (ii) Solid SO2 (iii) Solid CO2 (iv) Solid N2 Solution: Option (iii)Solid CO2 is the answer....
Read More →The most commonly used reducing
Question: The most commonly used reducing agent is (i) AlCl3 (ii) PbCl2 (iii) SnCl4 (iv) SnCl2 Solution: Option (iv) SnCl2 is the answer....
Read More →Write the equation of the normal to the curve
Question: Write the equation of the normal to the curve $y=\cos x$ at $(0,1)$. Solution: Given that $y=\cos x$ On differentiating both the sides w.r.t. $x$ $\frac{d y}{d x}=-\sin x$ Now, Slope of tangent at $(0,1)=0$ Equation of normal: $\left(\mathrm{y}-\mathrm{y}_{1}\right)=\frac{-1}{\text { Slope of tangent }}\left(\mathrm{x}-\mathrm{x}_{1}\right)$ $\Rightarrow(\mathrm{y}-1)=\frac{-1}{0}(\mathrm{x}-0)$ $\Rightarrow \mathrm{x}=0$...
Read More →Quartz is extensively used as a piezoelectric
Question: Quartz is extensively used as a piezoelectric material, it contains ___________. (i) Pb (ii) Si (iii) Ti (iv) Sn Solution: Option (ii)Si is the answer....
Read More →A compound X, of boron, reacts with NH3
Question: A compound X, of boron, reacts with NH3 on heating to give another compound Y which is called inorganic benzene. The compound X can be prepared by treating BF3 with Lithium aluminium hydride. The compounds X and Y are represented by the formulas. (i) B2H6, B3N3H6 (ii) B2O3, B3 N3 H6 (iii) BF3, B3N3 H6 (iv) B3N3H6, B2H6 Solution: Option (i)B2H6, B3N3H6 is the answer....
Read More →the midpoints of the sides BC, CA and AB of a ΔABC are D(2, 1), B
Question: the midpoints of the sides BC, CA and AB of a ΔABC are D(2, 1), B( - 5, 7) and P( - 5, - 5) respectively. Find the equations of the sides of ΔABC. Solution: Let us consider the coordinates of vertices of triangle A, B, C be (a, b), (c, d) and (e, f). Now using mid - point formula $(\mathrm{x}, \mathrm{y})=\left(\frac{\mathrm{x}_{1}+\mathrm{x}_{2}}{2}, \frac{\mathrm{y}_{1}+\mathrm{y}_{2}}{2}\right)$ For side BC (midpoint D): $(2,1)=\frac{c+e}{2}, \frac{d+f}{2}$ For side $\mathrm{AC}($ m...
Read More →In the structure of diborane
Question: In the structure of diborane (i) All hydrogen atoms lie in one plane and boron atoms lie in a plane perpendicular to this plane. (ii) 2 boron atoms and 4 terminal hydrogen atoms lie in the same plane and 2 bridging hydrogen atoms lie in the perpendicular plane. (iii) 4 bridging hydrogen atoms and boron atoms lie in one plane and two terminal hydrogen atoms lie in a plane perpendicular to this plane. (iv) All the atoms are on the same plane. Solution: Option (ii)2 boron atoms and 4 term...
Read More →Ionisation enthalpy (∆i H1 kJ mol–1) for the elements
Question: Ionisation enthalpy (∆i H1 kJ mol1) for the elements of Group 13 follows the order. (i) B Al Ga In Tl (ii) B Al Ga In Tl (iii) B Al Ga In Tl (iv) B Al Ga In Tl Solution: Option (iv)B Al Ga In Tl is the answer....
Read More →Write the coordinates of the point
Question: Write the coordinates of the point at which the tangent to the curve $y=2 x^{2}-x+1$ is parallel to the line $y=$ $3 x+9$ Solution: Let $(a, b)$ be the required coordinate. Given that the tangent to the curve $y=2 x^{2}-x+1$ is parallel to the line $y=3 x+9$. Slope of the line $=3$ $\because$ the point lies on the curve $\Rightarrow \mathrm{b}=2 \mathrm{a}^{2}-\mathrm{a}+1 \ldots$ (1) Now, $y=2 x^{2}-x+1$ $\Rightarrow \frac{\mathrm{dy}}{\mathrm{dx}}=4 \mathrm{x}-1$ Now value of slope a...
Read More →Silicon has a strong tendency to form polymers like silicones.
Question: Silicon has a strong tendency to form polymers like silicones. The chain length of silicone, a polymer can be controlled by adding (i) MeSiCl3 (ii) Me2SiCl2 (iii) Me3SiCl (iv) Me4Si Solution: Option (iii)Me3SiCl is the answer....
Read More →Catenation i.e., linking of similar atoms depends
Question: Catenation i.e., linking of similar atoms depends on size and electronic configuration of atoms. The tendency of catenation in Group 14 elements follows the order: (i) C Si Ge Sn (ii) C Si Ge Sn (iii) Si C Sn Ge (iv) Ge Sn Si C Solution: Option (ii) C Si Ge Snis the answer....
Read More →Boric acid is an acid because its molecule
Question: Boric acid is an acid because its molecule (i) contains replaceable H+ ion (ii) gives up a proton (iii) accepts OH from water releasing a proton (iv) combines with a proton from the water molecule Solution: Option (iii) accepts OH from water releasing a protonis the answer....
Read More →The exhibition of the highest co-ordination
Question: The exhibition of the highest co-ordination number depends on the availability of vacant orbitals in the central atom. Which of the following elements is not likely to act as a central atom in MF6 3? (i) B (ii) Al (iii) Ga (iv) In Solution: Option (i)B is the answer....
Read More →Write the slope of the normal to the curve
Question: Write the slope of the normal to the curve $y=\frac{1}{x}$ at the point $\left(3, \frac{1}{3}\right)$. Solution: Given that $y=\frac{1}{x}$ On differentiating both sides w.r.t. $x$, we get $\frac{d y}{d x}=-\frac{1}{x^{2}}$ Now, slope of the tangent at $\left(3, \frac{1}{3}\right)$ $\Rightarrow \frac{\mathrm{dy}}{\mathrm{dx}}=-\frac{1}{9}$ Slope of normal $=9$...
Read More →If A(4, 3), B(0, 0) and C(2, 3) are the vertices of a
Question: If A(4, 3), B(0, 0) and C(2, 3) are the vertices of a ΔABC, find the equation of the bisector of A. Solution: Construction: Draw a line from vertex A intersecting side BC of the triangle at D (as there is one bisector for exterior angle also but it is the default that we have to find interior angle bisector). As the angle between the sides AB and angle bisector AD and side AC and angle bisector AD is equal. $\angle \mathrm{A}=2 \theta \Rightarrow \angle \mathrm{BAD}=\angle \mathrm{CAD}...
Read More →Which of the following oxides is acidic?
Question: Which of the following oxides is acidic? (i) B2O3 (ii) Al2O3 (iii) Ga2O3 (iv) In2O3 Solution: Option (i)B2O3 is the answer...
Read More →The geometry of a complex species can be understood
Question: The geometry of a complex species can be understood from the knowledge of type of hybridisation of orbitals of the central atom. The hybridisation of orbitals of the central atom in [Be(OH)4] and the geometry of the complex are respectively (i) sp3, tetrahedral (ii) sp3, square planar (iii) sp3d2, octahedral (iv) dsp2, square planar Solution: Option (i) sp3, tetrahedralis the answer....
Read More →Which of the following is a Lewis acid?
Question: Which of the following is a Lewis acid? (i) AlCl3 (ii) MgCl2 (iii) CaCl2 (iv) BaCl2 Solution: Option (i)AlCl3 is the answer....
Read More →Write the angle between the curves
Question: Write the angle between the curves $y=e^{-x}$ and $y=e^{x}$ at their point of intersection. Solution: Given that $y=e^{-x} \ldots(1)$ and $y=e^{x}$. .......(2) Substituting the value of $y$ in (1), $e^{-x}=e^{x}$ $\Rightarrow x=0$ And $y=1($ from 2$)$ On differentiating (1) w.r.t. $x$, we get $\frac{\mathrm{dy}}{\mathrm{dx}}=\mathrm{e}^{-x}$ $\Rightarrow \mathrm{m}_{2}=\frac{\mathrm{dy}}{\mathrm{dx}}=1$ $\because m_{1} \times m_{2}=-1$ Since the multiplication of both the slopes is $-1...
Read More →The element which exists in a liquid
Question: The element which exists in a liquid state for a wide range of temperature and can be used for measuring high temperature is (i) B (ii) Al (iii) Ga (iv) In Solution: Option (iii)Ga is the answer....
Read More →Write the angle between the curves
Question: Write the angle between the curves $y^{2}=4 x$ and $x^{2}=2 y-3$ at the point $(1,2)$. Solution: Given two curves $y^{2}=4 x$ and $x^{2}=2 y-3$ Differentiating both the equations w.r.t. $x$, $\Rightarrow 2 y \frac{d y}{d x}=4$ and $2 x=2 \frac{d y}{d x}$ $\Rightarrow \frac{d y}{d x}=\frac{2}{y}$ and $\frac{d y}{d x}=x$ For $(1,2):$ $\Rightarrow \frac{\mathrm{dy}}{\mathrm{dx}}=\frac{2}{2}=1$ and $\frac{\mathrm{dy}}{\mathrm{dx}}=1$ Thus we get $\tan \theta=\left|\frac{\mathrm{m}_{1}-\mat...
Read More →Find the equations of the altitudes of a ΔABC
Question: Find the equations of the altitudes of a ΔABC, whose vertices are A(2, - 2), B(1, 1) and C( - 1, 0). Solution: Altitude: A line drawn from the vertex that meets the opposite side at right angles. It determines the height of the triangle. In triangle ABC, let the altitudes from vertices A, B and C are AL, BM and CN on sides BC,AC and AB respectively. Now we will find slope of sides and using the relation between the slopes of perpendicular lines i.e. m1.m2 $=-1$ we will find the slopes ...
Read More →Write the equation of the tangent to the curve
Question: Write the equation of the tangent to the curve $y=x^{2}-x+2$ at the point where it crosses the $y$-axis. Solution: Given that the curve $y=x^{2}-x+2$ has a point crosses the $y$-axis. The curve will be in the form of $(0, y)$ $\Rightarrow y=0-0+2$ $\Rightarrow y=2$ So, the point at which curve crosses the $y$-axis is $(0,2)$. Now, differentiating the equation of curve w.r.t. $x$ $\frac{d y}{d x}=x-1$ For $(0,2)$, $\frac{\mathrm{dy}}{\mathrm{dx}}=-1$ Equation of the tangent: $\left(\mat...
Read More →Assertion (A): Beryllium carbonate is kept in the atmosphere of carbon dioxide.
Question: Assertion (A): Beryllium carbonate is kept in the atmosphere of carbon dioxide. Reason (R): Beryllium carbonate is unstable and decomposes to give beryllium oxide and carbon dioxide. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct. (iv) A is not correct but R is correct. Solution: Option (i)Both A and R are correct and R is the correct explanation of Ais corre...
Read More →