Recent questions in Some basic concepts in chemistry

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For a reaction \(2 \mathrm{~A}+\mathrm{B} \rightarrow \mathrm{P}\), when concentration of \(\mathrm{B}\) alone is doubled, \(\frac{\mathrm{t}_{1}}{2}\) does not change and when concentrations of both \(A\) and \(B\) is doubled, rate increases by a factor of 4 . The unit of rate constant is,

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The total number of alkyl bromides (including stereoismers) formed in the reaction \(\mathrm{Me}_{3} \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}+\mathrm{HBr} \rightarrow\) will be

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In the extraction of \(\mathrm{Ca}\) by electro reduction of molten \(\mathrm{CaCl}_{2}\) some \(\mathrm{CaF}_{2}\) is added to the electrolyte for the following reason:

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The reaction for obtaining the metal (M) from its oxide \(\left(\mathrm{M}_{2} \mathrm{O}_{3}\right)\) ore is given by \(\mathrm{M}_{2} \mathrm{O}_{3}(\mathrm{~s})+2 \mathrm{Al}(\ell) \stackrel{\mathrm{Heat}}{\longrightarrow} \mathrm{Al}_{2} \mathrm{O}_{3}(\ell)+2 \mathrm{M}(\mathrm{s}),(\mathrm{s}=\) solid, \(\ell=\) liquid \()\) in that case, \(M\) is

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To a solution of a colourless efflorescent sodium salt, when dilute acid is added, a colourless gas is evolved along with formation of a white precipitate. Acidified dichromate solution turns green when the colourless gas is passed through it. The sodium salt is

asked Dec 11, 2021 in Some basic concepts in chemistry by kritika (90.1k points)

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Bond order of \(\mathrm{He}_{2}, \mathrm{He}_{2}^{+}\)and \(\mathrm{He}_{2}^{2+}\) are respectively:

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What will be the mass of one atom of \({ }^{12} \mathrm{C}\) ?

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Which of the following has the largest number of atoms?

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The difference between orbital angular momentum of an electron in a 4 f orbital and another electron in a 4 s orbital is

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How and why does the density of liquid water change on prolonged electrolysis?

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The number of unpaired electrons in the uranium \(\left({ }_{92} \mathrm{U}\right)\) atom is:

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Which of the following statements is not true for the reaction \(2 \mathrm{~F}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 4 \mathrm{HF}+\mathrm{O}_{2} ?\)

asked Dec 11, 2021 in Some basic concepts in chemistry by kritika (90.1k points)

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The radius of the first Bohr orbit of a hydrogen atom is \(0.53 \times 10^{-8} \mathrm{~cm}\). The velocity of the electron in the first Bohr orbit is

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\(\mathrm{K}_{\mathrm{t}}\) (water) \(=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\). The temperature at which ice begins to separate from a mixture of 10 mass \(\%\) ethylene glycol is

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An ideal gas expands adiabatically against vaccum. Which of the following is correct for the given process? (A) \(\Delta S=0\)

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Equal masses of ethane and hydrogen are mixed in a empty container at \(298 \mathrm{~K}\). The fraction of total pressure exerted by hydrogen is

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At \(273 \mathrm{~K}\) temperature and \(76 \mathrm{~cm} \mathrm{Hg}\) pressure, the density of a gas is \(1.964 \mathrm{gL}^{-1}\). The gas is

asked Dec 11, 2021 in Some basic concepts in chemistry by kritika (90.1k points)

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\(5 \mathrm{ml}\) of \(0.1 \mathrm{M} \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}\) is mixed with \(10 \mathrm{ml}\) of \(0.02 \mathrm{M} \mathrm{KI}\). The amount of Pbl \(_{2}\) precipitated will be about

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The mole fraction of ethanol in water is \(0.08\). Its molality is

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Among the following, the ion which will be more effective for flocculation of \(\mathrm{Fe}(\mathrm{OH})_{3}\) sol. is

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