List of top Chemistry Questions

At temperature $ T(K) $, the equilibrium constant $ K_c $ for the reaction: $$ \mathrm{AO_2(g) + BO_2(g) \rightleftharpoons AO_3(g) + BO(g)} $$ is 16. In a 1 L flask, one mole each of $\mathrm{AO_2}$, $\mathrm{BO_2}$, $\mathrm{AO_3}$, and $\mathrm{BO}$ are taken and heated to $ T(K) $. Identify the correct statements:
  • Total number of moles at equilibrium is 4
  • At equilibrium, the ratio of moles of $\mathrm{AO_2}$ and $\mathrm{AO_3}$ is 1:4
  • Total number of moles of $\mathrm{AO_2}$ and $\mathrm{BO_2}$ at equilibrium is 0.8
The following equilibrium is established at STP:
\[ B_2 (g) \rightleftharpoons 2B(g) \] Atoms of B occupy 20% of total volume at STP. The total pressure of the system is 1 bar. What is its \(K_p\)? (STP volume = 22.7 L)
At 298 K, the value of K\(_p\) for N\(_2\)O\(_4\)(g) \(\rightleftharpoons\) 2NO\(_2\)(g) is 0.113 atm. The partial pressure of N\(_2\)O\(_4\) at equilibrium is 0.2 atm. What is the partial pressure (in atm) of NO\(_2\) at equilibrium ?
At T(K), \( K_c \) value for the dissociation of \( \text{PCl}_5 \) is 0.04.
\[ \text{PCl}_5(g) \rightleftharpoons \text{PCl}_3(g) + \text{Cl}_2(g) \] The number of moles of \( \text{PCl}_5 \) to be added to a 3.0 L flask to get chlorine concentration of 0.15 mol L\(^{-1}\) is (approximately)?
At 298 K, the value of $K_c$ for the reaction A$_2$O$_4$(g) $\rightleftharpoons$ 2AO$_2$(g) is $x$ mol L$^{-1}$. What is the approximate $K_p$ value for this reaction?
Given: $R = 0.082$ L atm mol$^{-1}$ K$^{-1}$
At T(K), consider the following gaseous reaction, which is in equilibrium: N$_2$O$_5 \rightleftharpoons 2$NO$_2 + \frac{1}{2}$O$_2$. What is the fraction of N$_2$O$_5$ decomposed at constant volume and temperature, if the initial pressure is 300 mm Hg and pressure at equilibrium is 480 mm Hg? (Assume all gases as ideal)
Unit of \( K_C \) for equilibrium:
Given $K_p$ for $2AO_2 + O_2 \rightleftharpoons 2AO_3$ is $4 \times 10^{10}$. Find $K_p'$ for $3AO_3 \rightleftharpoons 3AO_2 + \frac{3}{2} O_2$.
What is the pH of 0.365% (w/V) HCl aqueous solution? (HCl=36.5 u), (log 0.365=−0.4377)
Consider the following:
Statement I:
\( \mathrm{H_2O_2} \) acts as an oxidising as well as reducing agent in both acidic and basic media.
Statement II:
10V \( \mathrm{H_2O_2} \) sample means it contains 6% (w/v) \( \mathrm{H_2O_2} \)
When 30 mL of 0.2 M \( NH_4OH \) is added to 30 mL of 2 M \( NH_4Cl \) solution. If the pH of the buffer formed is 8.2, what is the \( pK_b \) of \( NH_4OH \)?
At T(K), the following gaseous equilibrium is established. W + X \( \rightleftharpoons \) Y + Z The initial concentration of W is two times to the initial concentration of X. The system is heated to T(K) to establish the equilibrium. At equilibrium the concentration of Y is four times to the concentration of X. What is the value of \(K_c\)?
When 30 mL of 0.2 M \( NH_4OH \) is added to 30 mL of 2 M \( NH_4Cl \) solution. If the pH of the buffer formed is 8.2, what is the \( pK_b \) of \( NH_4OH \)?
At T(K), the following gaseous equilibrium is established. W + X \( \rightleftharpoons \) Y + Z The initial concentration of W is two times to the initial concentration of X. The system is heated to T(K) to establish the equilibrium. At equilibrium the concentration of Y is four times to the concentration of X. What is the value of \(K_c\)?
The molar solubility of PbI₂ in 0.2 M Pb(NO₃)₂ solution in terms of \(K_{sp}\) (solubility product) is
The number of moles of oxygen required for complete combustion of 2 moles of methane is:
Which of the following is not a buffer solution?
According to Le Chatelier’s principle, increasing pressure favours the reaction that:
For the reaction \( \mathrm{N_2 + 3H_2 \rightleftharpoons 2NH_3} \), \(\Delta H = -92\) kJ/mol. The equilibrium constant \(K_p\) will increase with:
Identify the sets containing correct order against the property mentioned from the following
Explain with reason:
(i) Cr^{2+} is a reducing agent while Mn^{3+} is an oxidising agent, while both have \(d^4\) configuration.}
Hoffmann Bromamide degradation reaction is given by:
Which of the following transition elements has both bcc and ccp structures at normal temperature?
If three elements A, B, C crystallize in a cubic solid lattice with B atoms at the cubic centres, C atoms at the centre of edges, and A atoms at the corners, then the formula of the compound is:
A metal crystallizes with hcp packing. The total number of voids, total number of tetrahedral voids and total number of octahedral voids are shown as A, B and C respectively. A, B and C in 0.25 moles of metal are respectively ($N_A$ = Avogadro number).