JEE Main Chemistry — Physical Chemistry previous year questions with solutions.
A weak acid HA has degree of dissociation x . Which option gives the correct expression of ( pH $\mathrm{pK}_{\mathrm{a}}$ )?
A vessel at 1000 K contains $\mathrm{CO}_2$ with a pressure of 0.5 atm . Some of $\mathrm{CO}_2$ is converted into CO on addition of graphite. If total pressure at equilibrium is 0.8 atm , then Kp is :
20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is ________ M. (Nearest Integer value) (Given : $\mathrm{Na}=23, \mathrm{I}=127, \mathrm{Ag}=108, \mathrm{~N}=14$, $\mathrm{O}=16 \mathrm{~g} \mathrm{~mol}^{-1}$)
For a reaction, $\mathrm{N}_2 \mathrm{O}_{5(\mathrm{~g})} \rightarrow 2 \mathrm{NO}_{2(\mathrm{~g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}$ in a constant volume container, no products were present initially. The final pressure of the system when $50 \%$ of reaction gets completed is
Which of the following binary mixture does not show the behaviour of minimum boiling azeotropes?
Which of the following graphs most appropriately represents a zero order reaction ?
Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given : Molar mass of Mg is $24 \mathrm{~g} \mathrm{~mol}^{-1}$.
The molar conductance of an infinitely dilute solution of ammonium chloride was found to be $185 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ and the ionic conductance of hydroxyl and chloride ions are 170 and $70 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-}$ ${ }^1$, respectively. If molar conductance of 0.02 M solution of ammonium hydroxide is $85.5 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$, its degree of dissociation is given by $\mathrm{x} \times 10^{-1}$. The value of $x$ is ________ (Nearest integer)
For hydrogen atom, the orbital/s with lowest energy is/are : (A) 4 s (B) $3 \mathrm{p}_x$ (C) $3 \mathrm{~d}_{x^2-y^2}$ (D) $3 \mathrm{~d}_{z^2}$ (E) $4 \mathrm{p}_z$ Choose the correct answer from the options given below :
A solution is made by mixing one mole of volatile liquid \(A\) with 3 moles of volatile liquid \(B\). The vapour pressure of pure A is 200 mm Hg and that of the solution is 500 mm Hg. The vapour pressure of pure \(B\) and the least volatile component of the solution, respectively, are :
Butane reacts with oxygen to produce carbon dioxide and water following the equation given below $\mathrm{C}_4 \mathrm{H}_{10}(\mathrm{~g})+\frac{13}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 4 \mathrm{CO}_2(\mathrm{~g})+5 \mathrm{H}_2 \mathrm{O}(\mathrm{l})$ If 174.0 kg of butane is mixed with 320.0 kg of $\mathrm{O}_2$, the volume of water formed in litres is ________.(Nearest integer) [Given : (a) Molar mass of $\mathrm{C}, \mathrm{H}, \mathrm{O}$ are 12, 1, $16 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively, (b) Density of water $\left.=1 \mathrm{~g} \mathrm{~mL}^{-1}\right]$
0.1 M solution of KI reacts with excess of $\mathrm{H}_2 \mathrm{SO}_4$ and $\mathrm{KIO}_3$ solutions. According to equation $5 \mathrm{I}^{-}+\mathrm{IO}_3^{-}+6 \mathrm{H}^{+} \rightarrow 3 \mathrm{I}_2+3 \mathrm{H}_2 \mathrm{O}$ Identify the correct statements : (A) 200 mL of KI solution reacts with 0.004 mol of $\mathrm{KIO}_3$ (B) 200 mL of KI solution reacts with 0.006 mol of $\mathrm{H}_2 \mathrm{SO}_4$ (C) 0.5 L of KI solution produced 0.005 mol of $\mathrm{I}_2$ (D) Equivalent weight of $\mathrm{KIO}_3$ is equal to ( $\frac{\text { Molecular weight }}{5}$ ) Choose the correct answer from the options given below :
Given below are two statements : Statement (I) : For a given shell, the total number of allowed orbitals is given by $\mathrm{n}^2$. Statement (II) : For any subshell, the spatial orientation of the orbitals is given by $-l$ to $+l$ values including zero. In the light of the above statements, choose the correct answer from the options given below :
If 1 mM solution of ethylamine produces $\mathrm{pH}=9$, then the ionization constant $\left(\mathrm{K}_{\mathrm{b}}\right)$ of ethylamine is $10^{-x}$. The value of $x$ is ______ (nearest integer). [The degree of ionization of ethylamine can be neglected with respect to unity.]
The pH of a 0.001 M HCl solution is:
An aqueous solution of HCl with pH 1.0 is diluted by adding equal volume of water (ignoring dissociation of water). The pH of HCl solution would (Given $\log 2=0.30)$
An organic compound weighing 500 mg , produced 220 mg of $\mathrm{CO}_2$. on complete combustion. The percentage composition of carbon in the compound is _____ \%. (nearest integer) (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1}$ of $\mathrm{C}: 12, \mathrm{O}: 16$)
For the given cell $\mathrm{Fe}^{2+}{ }_{(\mathrm{aq})}+\mathrm{Ag}^{+}{ }_{(\mathrm{aq})} \rightarrow \mathrm{Fe}_{(\mathrm{aq})}^{3+}+\mathrm{Ag}_{(\mathrm{s})}$ The standard cell potential of the above reaction is Given: $\begin{array}{lr} \mathrm{Ag}^{+}+\mathrm{e}^{-} \rightarrow \mathrm{Ag} & \mathrm{E}^\theta=\mathrm{xV} \\ \mathrm{Fe}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Fe} & \mathrm{E}^\theta=\mathrm{yV} \\ \mathrm{Fe}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Fe} & \mathrm{E}^\theta=\mathrm{zV} \end{array}$
Rate law for a reaction between A and B is given by $\mathrm{R}=\mathrm{k}[\mathrm{~A}]^{\mathrm{n}}[\mathrm{~B}]^{\mathrm{m}}$ If concentration of A is doubled and concentration of $B$ is halved from their initial value, the ratio of new rate of reaction to the initial rate of reaction $\left(\frac{r_2}{r_1}\right)$ is
Total number of non bonded electrons present in $\mathrm{NO}_2{ }^{-}$ion based on Lewis theory is
The amount of calcium oxide produced on heating 150 kg limestone ( $75 \%$ pure) is ______ kg. (Nearest integer) Given : Molar mass (in $\mathrm{g} \mathrm{mol}^{-1}$) of Ca-40, O-16, C-12
The molarity of a $70 \%$ (mass $/$ mass) aqueous solution of a monobasic acid $(\mathrm{X})$ is __________ $\times 10^{-1}$ M(Nearest integer) [Given: Density of aqueous solution of (X) is $1.25 \mathrm{~g} \mathrm{~mL}^{-1}$ Molar mass of the acid is $70 \mathrm{~g} \mathrm{~mol}^{-1}$ ]
0.01 mole of an organic compound $(X)$ containing $10 \%$ hydrogen, on complete combustion produced $0.9 \mathrm{~g} \mathrm{H}_2 \mathrm{O}$. Molar mass of $(\mathrm{X})$ is _____ $\mathrm{g} \mathrm{mol}^{-1}$.
$2.8 \times 10^{-3} \mathrm{~mol}$ of $\mathrm{CO}_2$ is left after removing $10^{21}$ molecules from its ' $x$ ' mg sample. The mass of $\mathrm{CO}_2$ taken initially is Given: $\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$