MASS SPECTROSCOPY

Question 1

Which of the following statement is false for mass spectroscopy?
a) Mass spectroscopy is used to identify unknown compounds within a sample, and to elucidate the structure and chemical properties of different molecules
b) Particle are characterized by their mass to charge ratios (m/z) and relative abundances
c) This technique basically studies the effect of ionizing energy on molecules
d) This technique can be used on all state of matter

Answer 1

d) This technique can be used on all state of matter

Question 2

Which of the following main component of mass spectroscopy deal with resolving the ions into their characteristics mass components according to their mass-to-charge ratio?
a) Ion Source
b) Analyzer
c) Detector System
d) Analyzer tube

Answer 2

b) Analyzer

Question 3

Who discovered the mass spectrometer?
a) Francis Aston
b) J. J Thomson
c) Ernest O. Lawrence
d) Walter Kaufmann

Answer 3

b) J. J Thomson

Question 4

In which state of matter mass spectroscopy is being performed?
a) solid
b) liquid
c) gaseous
d) plasma

Answer 4

c) gaseous

Question 5

A PMR spectrometer operates at 300 MHz. Find the value of magnetic field.
Given: gN = 5.585 and BN = 5.05 x 10-27 JT-I.
a) 7.05 T
b) 6.38 T
c) 7.58 T
d) 5.93 T

Answer 5

a) 7.05 T

Question 6

What are the main criteria on which mass spectrometer used for?
a) Composition in sample
b) Relative mass of atoms
c) Concentration of elements in the sample
d) Properties of sample

Answer 6

b) Relative mass of atoms

Question 7

A compound of molecular formula C8H7ClO shows a prominent band in its IR spectrum at 1690 cm-1. 1H NMR spectrum revealed only two major types of protons in the ratio of 5: 2. Which one of the following structures best fits the above data?

Answer 7

CH2COCL

Question 8

Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?
a) Alpha particles
b) Neutrons
c) Electrons
d) Protons

Answer 8

c) Electrons

Question 9

An organic compound Q exhibited the following spectral data obtained by mass spectroscopy.
IR: 1760 cm–1
1HNMR: chemical reference (ppm): 7.2 (IH, d, 16.0 Hz), 5.1 (IH, m), 2.1 (3H, s), 1.8 (3H, d, J = 7.0 Hz)
13CNMR chemical reference (ppm): 170 (carbonyl carbon). What is compound Q?

Answer 9

Me-O–O-Me

Question 10

The spectrum of a compound with molecular formula C5H602 is shown below. IR spectrum shows medium intensity band at 3270 and 2180 cm-1. What will be the structure of compound? Chemical reference: 1.3 (3H, t); 2.8 (1H, s), 4.3 (2H, q).

Answer 10

CH3-CH2-O-C–O-C—C-H

Question 11

Separation of ions in mass spectrometer take place on the basis of which of the following?
a) Mass
b) Charge
c) Molecular weight
d) Mass to charge ratio

Answer 11

d) Mass to charge ratio

Question 12

Which type of ionic species are allowed to pass through the slit and reach the collecting plate?
a) Negative ions of all masses
b) positive ions of the specific mass
c) Negative ions of the specific mass
d) Positive ions of all masses

Answer 12

b) positive ions of the specific mass