The slope of the tangent to the curve
Question: The slope of the tangent to the curve $x=t^{2}+3 t-8, y=2 t^{2}-2 t-5$ at point $(2,-1)$ is A. $\frac{22}{7}$ B. $\frac{6}{7}$ C. $-6$ D. $\frac{7}{6}$ Solution: Given that $x=t^{2}+3 t-8, y=2 t^{2}-2 t-5$ Differentiating both the sides, $\frac{\mathrm{dx}}{\mathrm{dt}}=2 \mathrm{t}+3, \frac{\mathrm{dy}}{\mathrm{dt}}=4 \mathrm{t}-2$ $\Rightarrow \frac{\mathrm{dy}}{\mathrm{dx}}=\frac{\frac{\mathrm{dy}}{\mathrm{dt}}}{\frac{\mathrm{dx}}{\mathrm{dt}}}$ $\Rightarrow \frac{d y}{d x}=\frac{\f...
Read More →Write a balanced chemical equation for the following reactions:
Question: Write a balanced chemical equation for the following reactions: (i) Permanganate ion (MnO4-) reacts with sulphur dioxide gas in acidic medium to produce Mn2+ and hydrogen sulphate ion. (Balance by ion-electron method) (ii) The reaction of liquid hydrazine (N2H4) with chlorate ion (ClO-3) in basic medium produces nitric oxide gas and chloride ion in the gaseous state. (Balance by oxidation number method) (iii) Dichlorine heptaoxide (Cl2O7) in gaseous state combines with an aqueous solut...
Read More →Nitric acid is an oxidising agent
Question: Nitric acid is an oxidising agent and reacts with PbO but it does not react with PbO2. Explain why? Solution: Nitric acid is an oxidizing agent and reacts with PbO to give a simple acid-base reaction without any change in oxidation state. In PbO2, Pb is in +4 oxidation state and cannot be oxidized further, hence no reaction takes place between PbO2 and HNO3....
Read More →PbO and PbO2 react with HCl according
Question: PbO and PbO2 react with HCl according to the following chemical equations: 2PbO + 4HCl 2PbCl2 + 2H2O PbO2 + 4HCl PbCl2 + Cl2 + 2H2O Why do these compounds differ in their reactivity? Solution: In reaction (i), none of the atoms changes. Therefore, it is not a redox reaction. It is an acid-base reaction because PbO is a basic oxide which reacts with HCl acid. The reaction (ii) is a redox reaction in which PbO2 gets reduced and acts as an oxidizing agent....
Read More →MnO42- undergoes disproportionation
Question: MnO42- undergoes disproportionation reaction in acidic medium but MnO4 does not. Give reason. Solution: In MnO4, Mn is in the highest oxidation state i.e. +7. Therefore, it does not undergo disproportionation. MnO42 undergoes disproportionation as follows : 3MnO42 + 4H+ 2MnO4 + MnO2+ 2H2O...
Read More →The reaction
Question: The reaction Cl2 (g) + 2OH- (aq) ClO- (aq) + Cl- (aq) + H2O (l) represents the process of bleaching. Identify and name the species that bleaches the substances due to its oxidising action. Solution: Hypochlorite ion is the species that bleaches the substance due to its oxidizing action....
Read More →Which of the following electrodes will act
Question: Which of the following electrodes will act as anodes, when connected to Standard Hydrogen Electrode? (i) Al/Al2+ -E\degree = 1.66 (ii) Fe/Fe2+ -E\degree = 0.44 (iii) Cu/Cu2+ -E\degree= + 0.34 (iv) F2 (g)/2F- (aq) -E\degree= + 2.87 Solution: Option (i) and (ii) are the answers....
Read More →Identify the correct statements with reference
Question: Identify the correct statements with reference to the given reaction P4 + 3OH+ 3H2O PH3+ 3H2PO2 (i) Phosphorus is undergoing reduction only. (ii) Phosphorus is undergoing oxidation only. (iii) Phosphorus is undergoing oxidation as well as reduction. (iv) Hydrogen is undergoing neither oxidation nor reduction. Solution: Option (iii) Phosphorus is undergoing oxidation as well as reductionand (iv)Hydrogen is undergoing neither oxidation nor reduction are the answers....
Read More →The exhibition of various oxidation states by
Question: The exhibition of various oxidation states by an element is also related to the outer orbital electronic configuration of its atom. Atom(s) having which of the following outermost electronic configurations will exhibit more than one oxidation state in its compounds. (i) 3s1 (ii) 3d1 4s2 (iii) 3d2 4s2 (iv) 3s2 3p3 Solution: Option (iii) 3d2 4s2 and (iv)3s2 3p3are the answers....
Read More →The equation of tangent
Question: The equation of tangent at those points where the curve $y=x^{2}-3 x+2$ meets $x$-axis are A. $x-y+2=0=x-y-1$ B. $x+y-1=0=x-y-2$ C. $x-y-1=0=x-y$ D. $x-y=0=x+y$ Solution: Given that the curve $y=x^{2}-3 x+2$ $\Rightarrow \frac{d y}{d x}=2 x-3$ The tangent passes through point $(x, 0)$ $\Rightarrow 0=x^{2}-3 x+2$ $\Rightarrow(x-2)(x-1)=0$ $\Rightarrow x=1$ or 2 Equation of the tangent: $\left(y-y_{1}\right)=$ Slope of tangent $x\left(x-x_{1}\right)$ Case: 1 When $x=2$ Slope of tangent $...
Read More →The exhibition of various oxidation states
Question: The exhibition of various oxidation states by an element is also related to the outer orbital electronic configuration of its atom. Atom(s) having which of the following outermost electronic configurations will exhibit more than one oxidation state in its compounds. (i) 3s1 (ii) 3d1 4s2 (iii) 3d2 4s2 (iv) 3s2 3p3 Solution: Option (iii) 3d2 4s2 and (iv) 3s2 3p3are the answers....
Read More →Find the slope of the line which makes an angle of
Question: Find the slope of the line which makes an angle of $30^{\circ}$ with the positive direction of the y-axis, measured anticlockwise. Solution: According to the given figure, the angle made by the line from X-axis is 90+30 $=120^{\circ}$ slope $=\left(\frac{y_{2}-y_{1}}{x_{2}-x_{1}}\right)$ We also know that slope of a line is equal to tan, Where $\theta=120^{\circ}$ $\tan \left(120^{\circ}\right)=\tan \left(90^{\circ}+30^{\circ}\right)=-\cot \left(30^{\circ}\right)=-\sqrt{3}$ Therefor th...
Read More →identify the correct statement (s)
Question: identify the correct statement (s) with the following reaction: Zn + 2HCl ZnCl2 + H2 (i) Zinc is acting as an oxidant (ii) Chlorine is acting as a reductant (iii) Hydrogen ion is acting as an oxidant (iv) Zinc is acting as a reductant Solution: Option (iii)Hydrogen ion is acting as an oxidant and (iv)Zinc is acting as a reductant are the answers....
Read More →Which of the following statement(s)
Question: Which of the following statement(s) is/are not true about the following decomposition reaction. 2KClO3 2KCl + 3O2 (i) Potassium is undergoing oxidation (ii) Chlorine is undergoing oxidation (iii) Oxygen is reduced (iv)None of the species is undergoing oxidation or reduction Solution: Option (i)Potassium is undergoing oxidation and (iv) None of the species is undergoing oxidation or reductionare the answers....
Read More →The equation of the normal to the curve
Question: The equation of the normal to the curve $3 x^{2}-y^{2}=8$ which is parallel to $x+3 y=k$ is A. $x-3 y=8$ B. $x-3 y+8=0$ C. $x+3 y \pm 8=0$ D. $x=3 y=0$ Solution: Given that the normal to the curve $3 x^{2}-y^{2}=8$ which is parallel to $x+3 y=k$. Let $(a, b)$ be the point of intersection of both the curve. $\Rightarrow 3 a^{2}-b^{2}=8 \ldots(1)$ and $a+3 b=k \ldots(2)$ Now, $3 x^{2}-y^{2}=8$ On differentiating w.r.t. $x$, $6 x-2 y \frac{d y}{d x}=0$ $\Rightarrow \frac{d y}{d x}=\frac{3...
Read More →Which of the following elements does not
Question: Which of the following elements does not show disproportionation tendency? (i) Cl (ii) Br (iii) F (iv) I Solution: Option (iii) F is the answer....
Read More →The vertices of a quadrilateral are A
Question: The vertices of a quadrilateral are A(-4, -2), B(2, 6), C(8, 5) and D(9, -7). Using slopes, show that the midpoints of the sides of the quad. ABCD from a parallelogram. Solution: The vertices of the given quadrilateral are A(-4,-2) B(2, 6), C(8, 5) and D(9, -7) The mid point of a line $A\left(x_{1}, y_{1}\right)$ and $B\left(x_{2}, y_{2}\right)$ is found out by $\left(\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}\right)$ Now midpoint of $A B=\left(\frac{-4+2}{2}, \frac{-2+6}{2}\right)=(...
Read More →Identify disproportionation reaction
Question: Identify disproportionation reaction (i) CH4 + 2O2 CO2 + 2H2O (ii) CH4 + 4Cl2 CCl4 + 4HCl (iii) 2F2 + 2OH- 2F- + OF2 + H2O (iv) 2NO2 + 2OH NO2-+ NO3-+ H2O Solution: Option (iv) 2NO2 + 2OH NO2-+ NO3- + H2O is the answer....
Read More →The largest oxidation number exhibited
Question: The largest oxidation number exhibited by an element depends on its outer electronic configuration. With which of the following outer electronic configurations the element will exhibit the largest oxidation number? (i) 3d1 4s2 (ii) 3d3 4s2 (iii) 3d5 4s1 (iv) 3d5 4s2 Solution: Option (iv)3d5 4s2 is the answer....
Read More →Which of the following arrangements
Question: Which of the following arrangements represent increasing oxidation number of the central atom? (i) CrO2-, CIO-3, CrO2-4, MnO-4 (ii) CIO-3, CrO2-4, MnO-4, CrO-2 (iii) CrO2+4, MnO-4, CrO-2, CIO3- (iv) CrO24-, MnO4-, CrO2-, CIO3- Solution: Option (i)CrO2-, CIO-3, CrO2-4, MnO-4 is the answer....
Read More →In which of the following compounds,
Question: In which of the following compounds, an element exhibits two different oxidation states. (i) NH2OH (ii) NH4NO3 (iii) N2H4 (iv) N3H Solution: Option (ii)NH4NO3 is the answer....
Read More →The oxidation number of an element in
Question: The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the following rules is not correct in this respect? (i) The oxidation number of hydrogen is always +1. (ii) The algebraic sum of all the oxidation numbers in a compound is zero. (iii) An element in the free or the uncombined state bears oxidation number zero. (iv) In all its compounds, the oxidation number of fluorine is 1. Solution: Option (i) The oxidation number of hydrogen is alway...
Read More →Thiosulphate reacts differently with
Question: Thiosulphate reacts differently with iodine and bromine in the reactions given below: 2S2O32-+ I2 S4O62-+ 2I S2O32-+ 2Br2+5H2O 2SO42-+ 2Br+ 10 H+ Which of the following statements justifies the above dual behaviour of thiosulphate? (i) Bromine is a stronger oxidant than iodine. (ii) Bromine is a weaker oxidant than iodine. (iii) Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions. (iv) Bromine undergoes oxidation and iodine undergoes a reduction in th...
Read More →Using the standard electrode potential,
Question: Using the standard electrode potential, find out the pair between which redox reaction is not feasible. EValues: Fe3+/ Fe2+ = +0.77; I2/I- = +0.54; Cu2+/ Cu = -0.34; Ag+ /Ag = + 0.80 V (i) Fe3+ and I- (ii) Ag+ and Cu (iii) Fe3+ and Cu (iv) Ag and Fe3+ Solution: Option (iv)Ag and Fe3+ is the answer....
Read More →Eᶱvalues of some redox couples is given below.
Question: Eᶱvalues of some redox couples is given below. Based on these values choose the correct option. Eᶱ values : Br2/Br= + 1.90; Ag+/Ag(s) = + 0.80 Cu2+/Cu(s) = + 0.34; I2(s)/I = + 0.54 (i) Cu will reduce Br (ii) Cu will reduce Ag (iii) Cu will reduce I (iv) Cu will reduce Br2 Solution: Option (iv)Cu will reduce Br2 is the answer....
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