Which of the following conditions shows
Question: Which of the following conditions shows the polluted environment. (i) a pH of rainwater is 5.6. (ii) amount of carbon dioxide in the atmosphere is 0.03%. (iii) biochemical oxygen demand 10 ppm. (iv) eutrophication Solution: Option (iii)biochemical oxygen demand 10 ppm and (iv)eutrophication are the answers....
Read More →Reduce the equation
Question: Reduce the equation $x+y-\sqrt{2}=0$ to the normal form $x \cos \alpha+y \sin \alpha=p$, and hence find the values of $\propto$ and $\mathrm{p}$. Solution: Given equation is $x+y-\sqrt{2}=0$ If the equation is in the form of $a x+b y=c$, to get into the normal form, we should divide it by $\sqrt{a^{2}+b^{2}}$, so now Divide by $\sqrt{1+1}=\sqrt{2}$ $\Rightarrow \frac{x}{\sqrt{2}}+\frac{y}{\sqrt{2}}=1$ This is in the form of $x \cos \alpha+y \sin \alpha=p$ $\cos \alpha=\frac{1}{\sqrt{2}...
Read More →Which of the following practices
Question: Which of the following practices will not come under green chemistry? (i) If possible, making use of soap made of vegetable oils instead of using synthetic detergents. (ii) Using H2O2 for bleaching purpose instead of using chlorine-based bleaching agents. (iii) Using a bicycle for travelling small distances instead of using petrol/diesel-based vehicles. (iv) Using plastic cans for neatly storing substances. Solution: Option (iv)Using plastic cans for neatly storing substances is the an...
Read More →Which of the following statements is correct?
Question: Which of the following statements is correct? (i) The ozone hole is a hole formed in the stratosphere from which ozone oozes out. (ii) The ozone hole is a hole formed in the troposphere from which ozone oozes out. (iii) The ozone hole is thinning of the ozone layer of the stratosphere at some places. (iv) Ozone hole means vanishing of ozone layer around the earth completely. Solution: Option (iii)The ozone hole is thinning of the ozone layer of the stratosphere at some placesis the ans...
Read More →The pollutants which come directly in
Question: The pollutants which come directly in the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants? (i) CO (ii) Hydrocarbon (iii) Peroxyacetyl nitrate (iv) NO Solution: Option (iii) Peroxyacetyl nitrate is the answer....
Read More →Dinitrogen and dioxygen are main
Question: Dinitrogen and dioxygen are main constituents of air but these do not react with each other to form oxides of nitrogen because of _________. (i) the reaction is endothermic and requires very high temperature. (ii) the reaction can be initiated only in the presence of a catalyst. (iii) oxides of nitrogen are unstable. (iv) N2and O2 are unreactive. Solution: Option (i)the reaction is endothermic and requires very high temperature is the answer....
Read More →Find the intervals in which the following functions are increasing or decreasing.
Question: Find the intervals in which the following functions are increasing or decreasing. $f(x)=x^{3}-6 x^{2}+9 x+15$ Solution: Given:- Function $f(x)=x^{3}-6 x^{2}+9 x+15$ Theorem:- Let $f$ be a differentiable real function defined on an open interval $(a, b)$. (i) If $f^{\prime}(x)0$ for $a l l_{x} \in(a, b)$, then $f(x)$ is increasing on $(a, b)$ (ii) If $f^{\prime}(x)0$ for all $x \in(a, b)$, then $f(x)$ is decreasing on $(a, b)$ Algorithm:- (i) Obtain the function and put it equal to $f(x...
Read More →The gaseous envelope around the earth
Question: The gaseous envelope around the earth is known as the atmosphere. The lowest the layer of this is extended up to 10 km from sea level, this layer is _________. (i) Stratosphere (ii) Troposphere (iii) Mesosphere (iv) Hydrosphere Solution: Option (ii)Troposphere is the answer....
Read More →Find the inclination of the line:
Question: Find the inclination of the line: (i) $x+\sqrt{3} y+6=0$ (ii) $3 x+3 y+8=0$ (iii) $\sqrt{3} \mathrm{x}-\mathrm{y}-4=0$ Solution: (i) Given equation is $x+\sqrt{3} y+6=0$ We can rewrite it as $\sqrt{3} y=-x-6$ $\Rightarrow y=\frac{-1}{\sqrt{3}} x+\frac{-6}{\sqrt{3}}$ It is in the form of $\mathrm{y}=\mathrm{x} \times \tan \alpha+\mathrm{c}$ Where $\tan \alpha=-\frac{1}{\sqrt{3}}$ and $\mathrm{c}=-\frac{6}{\sqrt{3}}$ The inclination of the line is $\alpha$ Therefore $\alpha=\tan ^{-1}\le...
Read More →Which of the following statements
Question: Which of the following statements about photochemical smog is wrong? (i) It has a high concentration of oxidising agents. (ii) It has a low concentration of the oxidising agent. (iii) It can be controlled by controlling the release of NO2 , hydrocarbons, ozone etc. (iv) Plantation of some plants like pinus helps in controlling photochemical smog. Solution: Option (ii)It has a low concentration of the oxidising agentis the answer....
Read More →Sewage containing organic waste should
Question: Sewage containing organic waste should not be disposed of in water bodies because it causes major water pollution. Fishes in such polluted water die because of (i) Large number of mosquitoes. (ii) Increase in the amount of dissolved oxygen. (iii) The decrease in the amount of dissolved oxygen in the water. (iv) Clogging of gills by mud. Solution: Option (iii)The decrease in the amount of dissolved oxygen in the water is the answer....
Read More →Which of the following statements is wrong?
Question: Which of the following statements is wrong? (i) Ozone is not responsible for the greenhouse effect. (ii) Ozone can oxidise sulphur dioxide present in the atmosphere to sulphur trioxide. (iii) The ozone hole is thinning of ozone layer present in the stratosphere. (iv) Ozone is produced in the upper stratosphere by the action of UV rays on oxygen. Solution: Option (i)Ozone is not responsible for the greenhouse effect is the answer....
Read More →Biochemical Oxygen Demand,
Question: Biochemical Oxygen Demand, (BOD) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be __________. (i) rich in dissolved oxygen. (ii) poor in dissolved oxygen. (iii) highly polluted. (iv) not suitable for aquatic life. Solution: Option (i)rich in dissolved oxygen is the answer....
Read More →Which of the following statements
Question: Which of the following statements is not true about classical smog? (i) Its main components are produced by the action of sunlight on emissions of automobiles and factories. (ii) Produced in a cold and humid climate. (iii) It contains compounds of reducing nature. (iv) It contains smoke, fog and sulphur dioxide. Solution: Option (i)Its main components are produced by the action of sunlight on emissions of automobiles and factoriesis the answer....
Read More →Find the intervals in which the following functions are increasing or decreasing.
Question: Find the intervals in which the following functions are increasing or decreasing. $f(x)=x^{8}+6 x^{2}$ Solution: Given:- Function $f(x)=x^{8}+6 x^{2}$ Theorem:- Let $f$ be a differentiable real function defined on an open interval $(a, b)$. (i) If $f^{\prime}(x)0$ for all $x \in(a, b)$, then $f(x)$ is increasing on $(a, b)$ (ii) If $f^{\prime}(x)0$ for all $x \in(a, b)$, then $f(x)$ is decreasing on $(a, b)$ Algorithm:- (i) Obtain the function and put it equal to $f(x)$ (ii) Find $f^{\...
Read More →Photochemical smog occurs in a warm,
Question: Photochemical smog occurs in a warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog, identify it. (i) NO2 (ii) O3 (iii) SO2 (iv) Unsaturated hydrocarbon Solution: Option (iii)SO2 is the answer....
Read More →Which of the following gases
Question: Which of the following gases is not a greenhouse gas? (i) CO (ii) O3 (iii) CH4 (iv) H2O vapour Solution: Option (i)CO is the answer....
Read More →Reduce the equation 5x – 12y = 60 to intercepts form.
Question: Reduce the equation 5x 12y = 60 to intercepts form. Hence, find the length of the portion of the line intercepted between the axes Solution: Given equation is $5 x-12 y=60$ We can rewrite it as $\frac{5}{60} x-\frac{12}{60} y=1$ $\Rightarrow \frac{x}{12}-\frac{y}{5}=1$ $\Rightarrow \frac{x}{12}+\frac{y}{-5}=1$ This equation is in the slope intercept form i.e. in the form $\frac{x}{a}+\frac{y}{b}=1$ Where, $x$-intercept $=12$ and $y$-intercept $=-5$ Two points are: $(12,0)$ on the $x$-a...
Read More →Find the intervals in which the following functions are increasing or decreasing.
Question: Find the intervals in which the following functions are increasing or decreasing. $f(x)=5 x^{\frac{3}{2}}-3 x^{\frac{5}{2}}, x0$ Solution: Theorem:- Let $f$ be a differentiable real function defined on an open interval $(a, b)$. (i) If $f^{\prime}(x)0$ for all $x \in(a, b)$, then $f(x)$ is increasing on $(a, b)$ (ii) If $f^{\prime}(x)0$ for all $x \in(a, b)$, then $f(x)$ is decreasing on $(a, b)$ Algorithm:- (i) Obtain the function and put it equal to $f(x)$ (ii) Find $f^{\prime}(x)$ (...
Read More →Reduce the equation 3x – 4y + 12 = 0 to intercepts form.
Question: Reduce the equation 3x 4y + 12 = 0 to intercepts form. Hence, find the length of the portion of the line intercepted between the axes Solution: Given equation is $3 x-4 y+12=0$ We can rewrite it as $3 x-4 y=-12$ $\Rightarrow \frac{3}{-12} \mathrm{x}+\frac{4}{12} \mathrm{y}=1$ $\Rightarrow \frac{\mathrm{x}}{-4}+\frac{\mathrm{y}}{3}=1$ This equation is in the slope intercept form i.e. in the form $\frac{x}{a}+\frac{y}{b}=1$ Where, $x$-intercept $=-4$ and $y$-intercept $=3$ Two points are...
Read More →Assertion (A): Among isomeric pentanes,
Question: Assertion (A): Among isomeric pentanes, 2, 2-dimethylpentane has the highest boiling point. Reason (R): Branching does not affect the boiling point. (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 (iii)Both A and R are not correct is correct....
Read More →Assertion (A): Nitration of benzene with nitric acid
Question: Assertion (A): Nitration of benzene with nitric acid requires the use of concentrated sulphuric acid. Reason (R): The mixture of concentrated sulphuric acid and concentrated nitric acid produces the electrophile, NO2+. (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) is correct...
Read More →Reduce the equation y + 5 = 0 to slope-intercept form,
Question: Reduce the equation y + 5 = 0 to slope-intercept form, and hence find the slope and the y-intercept of the line. Solution: Given equation is y + 5 = 0 We can rewrite it as $y=-5$ This equation is in the slope-intercept form, i.e. it is the form of $y=m \times x+c$, where $m$ is the slope of the line and $c$ is $y$-intercept of the line Therefore, m = 0 and c = - 5 Conclusion: Slope is 0 and $y$-intercept is $-5$...
Read More →Assertion (A): Toluene on Friedel Crafts methylation
Question: Assertion (A): Toluene on Friedel Crafts methylation gives o and pxylene. Reason (R): CH3-group bonded to benzene ring increases electron density at o and p position. (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) is correct...
Read More →Assertion (A): The compound cyclooctane has the following structural
Question: Assertion (A): The compound cyclooctane has the following structural formula: It is cyclic and has conjugated 8-electron system but it is not an aromatic compound. Reason (R) : (4n + 2) electrons rule does not hold good and the ring is not planar. (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) is c...
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