Q. The entropy change for the melting of ‘x’ moles of ice (heat of fusion is 80 cal g–1) at 273 K and 1 atm pressure is 28.80 cal K–1. The value of ‘x’ is___________. (Round off to two decimal places) (Molecular weight of water =18 g/mol) Solution: Δ S = Δ H/ T , OR Δ […]
Q. An ideal gas occupies an unknown volume V liters (L) at a pressure of 12 atm. The gas is expanded isothermally against a constant external pressure of 2 atm so that its final volume becomes 3 L. The work involved for this expansion process is______cal. (Round off to two decimal places) (Gas constant R
Q. On heating a sample of 25 mg hydrated compound (molecular weight = 250 g/mol) in thermogravimetric analysis, 16 mg of dehydrated compound remains. The number of water molecules lost per molecule of hydrated compound is . (Molecular weight of water = 18 g/mol) Solution: 25 mg Compound contains (25-16) g of Water = 9
Q. The number of 1H NMR signals observed for the following compound is Ans: The number of 1H NMR signals observed for the following compound is 6 Solution: Enantiotropic protons are protons that are replaced by another group of protons. They have the same mirror image and chemical shift in the NMR spectrum. Therefore, Here
The number of 1H NMR signals observed for the following compound is Read More »
Q. The number of following diene(s) that undergo Diels-Alder reaction with methyl acrylate is Ans: The number of following diene(s) that undergo Diels-Alder reaction with methyl acrylate is 5 Solution: Diels- Alder Reaction is a pericyclic chemical reaction between substituted alkenes or Dienophiles and conjugated dienes. Here, all the cis structures will undergo Diels- Alder Reaction
Q. Among the following compounds, the number of compounds that DO NOT exhibit optical activity at room temperature is Ans: 4 Among the following compounds, the number of compounds that DO NOT exhibit optical activity at room temperature is 4.
Q. In the following reaction, the stereochemistry of the major product is predicted by the (A) Cram’s model (B) Cram’s chelation model (C) Felkin model (D) Felkin-Anh model Ans: Cram’s chelation model
In the following reaction, the stereochemistry of the major product is predicted by the Read More »
Q. The Woodward-Hoffmann condition to bring out the following transformation is (A) ∆, conrotatory (B) ∆, disrotatory (C) hν, disrotatory (D) hν, conrotatory Ans: hν, conrotatory
The Woodward-Hoffmann condition to bring out the following transformation is Read More »
Q. Consider the following phase diagram of CO2 (not to scale). At equilibrium, the INCORRECT statement is: A. At 200 K, on increasing the pressure from 1 to 50 atm, CO2 gas condenses to liquid. B. It is not possible to obtain liquid CO2 from gaseous CO2 below 5.11 atm. C. Both liquid and gas
Q. Micelle formation is accompanied by the (A) decrease in overall entropy due to ordering. (B) increase in overall entropy mostly due to increase in solvent entropy. (C) increase in overall entropy mostly due to increase in solute entropy. (D) increase in overall entropy and decrease in enthalpy. Ans: increase in overall entropy mostly due
