Description : All mammalian steroid hormones are formed from (A) Purine (B) Pyrimidine (C) Cholesterol (D) Pyrrole
Last Answer : Answer : C
Description : During breakdown of haem, the methenyl bridge between the following two pyrrole rings is broken: (A) I and II (B) II and III (C) III and IV (D) IV and I
Last Answer : Answer : A
Description : Vitamin B12 has a complex ring structure (corrin ring) consisting of four (A) Purine rings (B) Pyrimidine rings (C) Pyrrole rings (D) Pteridine rings
Description : Which of the following is not a sulphur compound present in petroleum? (A) Thiophenes (B) Mercaptans (C) Sulphones (D) Pyrrole
Last Answer : (D) Pyrrole
Description : Chlorophyll a molecule at its carbon atom 3 of the pyrrole ring II has one of the following (a) carboxylic group (b) magnesium (c) aldehyde group (d) methyl group
Last Answer : d) methyl group.
Description : Furan reacts with ammonia in the presence of alumina at 400°C to give (a) Pyridine (b) Furfural (c) Pyrrole (d) Furoic acid
Last Answer : Pyrrole
Description : Which of the following reagents will react with pyrrole to form 2- formylpyrrole? (a) HCOOH (b) CHCl3/KOH (c) H2O2 (d) (CH3CO)2O/SnCl4
Last Answer : CHCl3/KOH
Description : Pyrrole is less basic than pyridine because the lone-pair of electrons on Natom in pyrrole (a) is part of the delocalized π molecular orbital. (b) is not part of the delocalized π molecular orbital. (c) resides in sp2 hybrid orbital (d) resides in sp hybrid orbital
Last Answer : is part of the delocalized π molecular orbital.
Description : Which of the following heterocyclic compounds is not aromatic? (a) Pyridine (b) Pyrrole (c) Furan (d) Piperidine
Last Answer : Piperidine
Description : An isosteric replacement for carboxylic acid group is (A) pyrrole (B) isoxazole (C) phenol (D) tetrazole
Last Answer : (D)tetrazole
Description : Pyrrole is ...... a. nonaromatic b. Aromitic c. Antiaromatic d. Aliphatic
Last Answer : b. Aromitic
Description : (A) Nucleophiles attack the regions of high electron density. (R) Nucleophiles act as Lewis bases.
Last Answer : (A) Nucleophiles attack the regions of high electron density. (R) Nucleophiles act as Lewis bases. A. If ... IF (A) is incorrect but (R) is correct.
Description : Assertion: Phenol is more reactive than benzene towards electrophilic reactions. Reason : The +R effect of OH group increases the electron density on
Last Answer : Assertion: Phenol is more reactive than benzene towards electrophilic reactions. Reason : The +R effect of ... D. A is incorrect but R is correct
Description : At room temperature copper has free electron density of `8.4xx10^(28) per m^(3)` . The copper conductor has a cross-section of `10^(-6)m^(2)` and carr
Last Answer : At room temperature copper has free electron density of `8.4xx10^(28) per m^(3)` . The copper conductor has a cross ... . `4cms^(-1)` D. `0.4mms^(-1)`
Description : Mean drift velocity of electron in a copper wire having cross-sectional area 5.0 × 10-6 m2 carrying current of 1 A and having number density 8.5 × 1028 m3 is A. 0.015 mm s-1 B. 0.1 mm s-1 C. 0.5 mm s-1 D. 0.25 mm s-1
Last Answer : 0.015 mm s-1
Description : Number of conduction electrons per unit volume is A. electron number B. number density C. proton number D. neutron numbe
Last Answer : number density
Description : Semiconductors have electron number density of order A. 1024 m-3 B. 1020 m-3 C. 1012 m-3 D. 1023 m-3
Last Answer : 1023 m-3
Description : An electron is travelling at right angles to a uniform magnetic field of flux density 1.2 mT with a speed of 8 × 106 m s-1, the radius of circular path followed by electron is A. 3.8 cm B. 3.7 cm C. 3.6 cm D. 3.5 cm
Last Answer : 3.8 cm
Description : Calculate the electric field when the conductivity is 20 units, electron density is 2.4 units and the velocity is 10m/s. Assume the conduction and convection current densities are same. a) 2.4 b) 4.8 c) 3.6 d) 1.2
Last Answer : d) 1.2
Description : Find the electron density when convection current density is 120 units and the velocity is 5m/s. a) 12 b) 600 c) 24 d) 720
Last Answer : c) 24
Description : Calculate the convection current when electron density of 200 units is travelling at a speed of 12m/s. a) 16.67 b) 2400 c) 2880 d) 0.0
Last Answer : b) 2400
Description : Which of the following properties distinguish a material as conductor, insulator and semiconductor? a) Free electron charges b) Fermi level after doping c) Energy band gap d) Electron density
Last Answer : c) Energy band gap
Description : Phenol is an ortho-para director because the hydroxyl group : (a) donates electrons that increase electron density at ortho and para positions favoring nucleophilic attack. (b) donates ... para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.
Last Answer : donates electrons that increase electron density at ortho and para positions favoring electrophilic attack.
Description : Answer: They are regions of space around the nucleus where the probability of finding an electron is maximum.
Last Answer : Which cells are programmed to die during embryonic stage?
Description : The maximum electron capacity of any orbital is (a) 2 (b) 6 (c) 14 (d) Cannot be determined unless the principal quantum number is known
Last Answer : Ans:(a)
Description : The following particles move with same kinetic energy. Which of them has maximum momentum? (1) Electron (2) Proton (3) Deutron (4) Alpha Particle
Last Answer : (4) Alpha Particle Explanation: The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P^2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
Description : Halogens have maximum negative electron gain enthalpy in the respective periods in the P. T Why ?
Last Answer : Ans Due to smallest size and high effective nuclear charge , readily accept one electron to acquire noble gas electronic configuration
Description : The following particles move with same kinetic energy. Which of them has maximum momentum ? (1) Electron (2) Proton (3) Deutron (4) Alpha Particle
Last Answer : Alpha Particle
Description : In order to generate electron-hole pairs, the maximum wavelength of radiation for Silicon (Band gap = 1.1 eV) is (a) 1.88 μm (b) 1.68 μm (c) 1.13 μm (d) 1.54 μm
Last Answer : In order to generate electron-hole pairs, the maximum wavelength of radiation for Silicon (Band gap = 1.1 eV) is 1.13 μm