In the following system, textPCl5(g) ightleftharpoons textPCl*3(g)+textCl*2(g) at equilibrium, upon addition of xenon gas at constant T & p, the concentration of:

Solution & Explanation

### Core Logic When an inert gas like Xenon is added at constant temperature and pressure, the total volume of the container must expand significantly to maintain constant pressure. According to Le Chatelier's principle, the equilibrium shifts towards the side with a higher number of gas moles (the forward direction here, since Delta n_g = 1 > 0). This increases the absolute number of moles of textPCl_3 and textCl_2. ### Step 1: Concentration Analysis Concentration is calculated as moles divided by total volume ([textX] = fracnV). Even though the forward shift generates a few more moles of products, the fractional volume expansion factor is larger. Thus, the actual molar concentrations of **all species** (textPCl_5, textPCl_3, and textCl_2) ultimately decrease. ### Pattern Recognition Trap Alert: Distinguish clearly between "moles" and "concentration". The forward shift increases product moles, but the volume expansion dilutes all chemical species, dropping total concentration values. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Chemical Equilibrium

Reference Study Guides

Chemical Equilibrium

More Chemical Equilibrium Previous-Year Questions — Page 6

Q62 jee_main_2024_31_jan_morning Equilibrium Constant
For the given reaction, choose the correct expression of K_C from the following :- Fe_(aq)^3+ + SCN_(aq)^- rightleftharpoons (FeSCN)_(aq)^2+
  • A. K_C = frac[FeSCN^2+][Fe^3+][SCN^-]
  • B. K_C = frac[Fe^3+][SCN^-][FeSCN^2+]
  • C. K_C = frac[FeSCN^2+][Fe^3+]^2[SCN^-]^2
  • D. K_C = frac[FeSCN^2+]^2[Fe^3+][SCN^-]

Solution

### Related Formula K_C = frac[textProducts][textReactants] ### Core Logic K_C = fractextProducts ion conc.textReactants ion conc. K_C = frac[FeSCN^2+][Fe^3+][SCN^-] ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium

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