The mechanism of
Question: The mechanism of $S_{N}{ }^{1}$ reaction is given as : A student writes general characteristics based on the given mechanism as : (a) The reaction is favoured by weak nucleophiles (b) $R^{\oplus}$ would be easily formed if the substituents are bulky (c) The reaction is accompained by recemization (d) The reaction is favoured by non-polar solvents. Which observations are correct ? b and d$\mathrm{a}$ and $\mathrm{c}$$a, b$ and $c$$\mathrm{a}$ and $\mathrm{b}$Correct Option: , 2 Solution...
Read More →Cast iron is used for the manufacture of :
Question: Cast iron is used for the manufacture of :wrought iron and pig ironwrought iron and steelwrought iron, pig iron and steelpig iron, scrap iron and steelCorrect Option: , 2 Solution: Cast iron is used for manufacturing of wrought iron and steel....
Read More →The Kjeldahl method of Nitrogen estimation fails
Question: The Kjeldahl method of Nitrogen estimation fails for which of the following reaction products ? a and dc and $\mathrm{d}$$\mathrm{a}, \mathrm{c}$ and $\mathrm{d}$$b$ and $c$Correct Option: 2, Solution: Kjeldahl method is used for $\mathrm{N}$ estimation But not given by 'Diazo' compounds...
Read More →Arrange the following labelled hydrogens
Question: Arrange the following labelled hydrogens in decreasing order of acidity : $bcda$$\mathrm{c}\mathrm{b}\mathrm{a}\mathrm{d}$$bacd$$cbda$Correct Option: 1 Solution: Acidic strength order :...
Read More →If you spill a chemical toilet cleaning liquid on your hand,
Question: If you spill a chemical toilet cleaning liquid on your hand, your first aid would be :aqueous $\mathrm{NH}_{3}$vinegaraqueous $\mathrm{NaHCO}_{3}$aqueous $\mathrm{NaOH}$Correct Option: , 3 Solution: Toilet cleaning liquid has about $10.5 \% \mathrm{w} / \mathrm{v}$ $\mathrm{HCl}$; to neutralise its affect aqueous $\mathrm{NaHCO}_{3}$ is used while $\mathrm{NaOH}$ is avoid for this purpose because its highly corosive in nature and can burn body....
Read More →The major product of the following reaction is:
Question: The major product of the following reaction is: Correct Option: , 3 Solution:...
Read More →Aqua regia is used for dissolving noble metals
Question: Aqua regia is used for dissolving noble metals (Au, Pt, etc). The gas evolved in this process is :$\mathrm{N}_{2}$$\mathrm{N}_{2} \mathrm{O}_{3}$NO$\mathrm{N}_{2} \mathrm{O}_{5}$Correct Option: , 3 Solution: $\mathrm{Au}+\mathrm{HNO}_{3}+4 \mathrm{HCl} \rightarrow \mathrm{HAuCl}_{4}+\mathrm{NO}+2 \mathrm{H}_{2} \mathrm{O}$...
Read More →The electronic spectrum of
Question: The electronic spectrum of $\left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ shows a single broad peak with a maximum at $20,300 \mathrm{~cm}^{-1}$. The crystal field stabilization energy (CFSE) of the complex ion, in $\mathrm{kJ} \mathrm{mol}^{-1}$, is :$242.5$$83.7$$145.5$97Correct Option: 4, Solution: $\mathrm{CFSE}=0.4 \Delta_{0}$ $=0.4 \times \frac{20300}{83.7}$ $=97 \mathrm{~kJ} / \mathrm{mol}$...
Read More →The internal energy change (in J) when 90g of water undergoes complete
Question: The internal energy change (in $\mathrm{J}$ ) when $90 \mathrm{~g}$ of water undergoes complete evaporation at $100^{\circ} \mathrm{C}$ is (Given : $\Delta \mathrm{H}_{\text {vap }}$ for water at $373 \mathrm{~K}=41 \mathrm{~kJ} / \mathrm{mol}$, $\mathrm{R}=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$ ) Solution: $\mathrm{H}_{2} \mathrm{O}(\ell) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \quad 90 \mathrm{gm}$ of $\mathrm{H}_{2} \mathrm{O}$ $\Delta \mathrm{H}=\Delta \mathrm{...
Read More →Thermal power plants can lead to :
Question: Thermal power plants can lead to :Ozone layer depletionEutrophicationAcid rainBlue baby syndromeCorrect Option: , 3 Solution: Thermal power plants lead to acid rain....
Read More →Tyndall effect of observed when :
Question: Tyndall effect of observed when : The diameter of dispersed particles is much smaller than the wavelength of light usedThe diameter of dispersed particles is much larger than the wavelength of light usedThe diameter of dispersed particles is similar to the wavelength of light usedThe refractive index of dispersed phase is greater than that of the dispersion mediumCorrect Option: , 3 Solution: The diameter of disperseed particles is similar to wavelength of light used....
Read More →The oxidation states of iron atoms in compounds (A), (B) and (C), respectively,
Question: The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are $x, y$ and $z$. The sum of $x, y$ and $z$ is Solution: (A) $\mathrm{Na}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{5}(\mathrm{NOS})\right]$ $(+1) 4+x+(-1) 5+(-1) 1=0$ $x=+2$ (B) $\mathrm{Na}_{4}\left[\mathrm{Fe} \mathrm{O}_{4}\right]$ $(+1) 4+y+(-2) 4=0$ $y=+4$ (C) $\left[\mathrm{Fe}_{2}^{\mathrm{z}}(\mathrm{CO})_{9}\right]$ $2 z+0 \times 9=0$ $Z=0$ so $(x+y+z)=+2+4+0$ $=6$...
Read More →The number of chiral carbons present in
Question: The number of chiral carbons present in the molecule given below is________. Solution: No. of chiral centres...
Read More →Solve this following
Question: Henry's constant (in kbar) for four gases $\alpha, \beta$, $\gamma$ and $\delta$ in water at $298 \mathrm{~K}$ is given below : (density of water $=10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ at $298 \mathrm{~K}$ ) This table implies that: The pressure of a $55.5$ molal solution of $\gamma$ is 1 barThe pressure of a $55.5$ molal solution of $\delta$ is 250 barSolubility of $\gamma$ at $308 \mathrm{~K}$ is lower than at $298 \mathrm{~K}$$\alpha$ has the highest solubility in water at a given ...
Read More →The mass of gas adsorbed, x, per unit mass of adsorbate,
Question: The mass of gas adsorbed, $x$, per unit mass of adsorbate, $\mathrm{m}$, was measured at various pressures, p. A graph between $\log \frac{x}{m}$ and $\log p$ gives a straight line with slope equal to 2 and the intercept equal to $0.4771$. The value of $\frac{x}{m}$ at a pressure of $4 \mathrm{~atm}$ is : (Given $\log 3=0.4771$ ) Solution: $\frac{x}{m}=k p^{x}$.....(1) Given $\mathrm{c}=\log \mathrm{k}=0.4771$ or $\mathrm{k}=3$ slope $x=2$ put in eq. (1) $\frac{\mathrm{x}}{\mathrm{m}}=...
Read More →Which of the following compounds produces
Question: Which of the following compounds produces an optically inactive compound on hydrogenation ?Correct Option: , 2 Solution:...
Read More →The Gibbs energy change (in J) for the given reaction at
Question: The Gibbs energy change (in J) for the given reaction at $\left[\mathrm{Cu}^{2+}\right]=\left[\mathrm{Sn}^{2+}\right]=1 \mathrm{M}$ and $298 \mathrm{~K}$ is: Official Ans. by NTA $(96500.00)$ Solution: $\Delta \mathrm{G}=\Delta \mathrm{G}^{\circ}+\mathrm{RT} \ln \left[\frac{\mathrm{Sn}^{+2}}{\mathrm{Cu}^{+2}}\right]$ $=-2 \times 96500[(-0.16)-0.34]+\mathrm{RT} \ln \left(\frac{1}{1}\right)$ $=96500 \mathrm{~J}$...
Read More →It is true that:
Question: It is true that:A zero order reaction is a single step reactionA second order reaction is always a multistep reactionA first order reaction is always a single step reactionA zero order reaction is a multistep reactionCorrect Option: , 4 Solution: Zero order reaction is multiple step reaction....
Read More →Which of the following is used for the preparation of colloids ?
Question: Which of the following is used for the preparation of colloids ?Ostwald ProcessVan Arkel MethodBredig's Arc MethodMond ProcessCorrect Option: , 3 Solution: Bredig's Arc method is used to from metal colloids....
Read More →In a molecule of pyrophosphoric acid, the
Question: In a molecule of pyrophosphoric acid, the number of $\mathrm{P}-\mathrm{OH}, \mathrm{P}=\mathrm{O}$ and $\mathrm{P}-\mathrm{O}-\mathrm{P}$ bonds/ moiety(ies) respectivey are :3,3 and 32,4 and 14,2 and 04,2 and 1Correct Option: , 4 Solution: Pyrophosphoric acid. $\mathrm{P}-\mathrm{OH}$ linkages $=4$ $P=O$ linkages $=2$ $\mathrm{P}-\mathrm{O}-\mathrm{P}$ linkages $=1$...
Read More →The major product in the following reaction is :
Question: The major product in the following reaction is : Correct Option: , 3 Solution:...
Read More →If the boiling point of
Question: If the boiling point of $\mathrm{H}_{2} \mathrm{O}$ is $373 \mathrm{~K}$, the boiling point of $\mathrm{H}_{2} \mathrm{~S}$ will be :Greater than $300 \mathrm{~K}$ but less than $373 \mathrm{~K}$Less than $300 \mathrm{~K}$Equal to $373 \mathrm{~K}$More than $373 \mathrm{~K}$Correct Option: , 2 Solution: Boiling point of $\mathrm{H}_{2} \mathrm{~S}$ Boiling point of $\mathrm{H}_{2} \mathrm{O}$ $(213 \mathrm{~K})$ $(373 \mathrm{~K})$...
Read More →Consider the following reactions :
Question: Consider the following reactions : ' $x$ ', ' $y$ ' and ' $z$ ' in these reactions are respectively.$5,6, \ 5$$4,5 \ 5$$5,4 \ 5$$4,6 \ 5$Correct Option: , 4 Solution: due to presence of - OH group in Glucose the reaction is...
Read More →An organic compound
Question: An organic compound [A], molecular formula $\mathrm{C}_{10} \mathrm{H}_{20} \mathrm{O}_{2}$ was hydrolyzed with dilute sulphuric acid to give a carboxylic acid [B] and alcohol [C]. Oxidation of [C] with $\mathrm{CrO}_{3}-\mathrm{H}_{2} \mathrm{SO}_{4}$ produced [B]. Which of the following structures are not possible for $[\mathrm{A}]$ ? $\left(\mathrm{CH}_{3}\right)_{3}-\mathrm{C}-\mathrm{COOCH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{3}$$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}...
Read More →While titrating dilute HCl solution with aqueous
Question: While titrating dilute $\mathrm{HCl}$ solution with aqueous $\mathrm{NaOH}$, which of the following will not be required?Clamp and phenolphthaleinPipette and distilled waterBurette and porcelain tileBunsen burner and measuring cylinderCorrect Option: , 4 Solution: Lab manual...
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