Question 1

Which of the following best describes the function of the salt bridge in a galvanic cell?

Accepted Answer

It maintains electrical neutrality by allowing ion migration between half-cells.

Question 2

A solution contains 0.01 M ZnSO$$_4$$ and a Zn electrode at 25°C. Using the Nernst equation, what is the half-cell potential if $$E^0$$_{$$Zn^{2+}/Zn$$} = -0.76$$ V?$$ 
$$
$$Nernst equation: $$
$$
$$E = E^0$ - \frac{0.0592}{n} \log Q$

Accepted Answer

$$-0.82 V$$

Question 3

Which type of electrode is used as a reference electrode in potentiometric measurements and has a standard potential of 0.2444 V?

Accepted Answer

Standard Calomel Electrode (SCE)

Question 4

In a colorimetric analysis, why is a blank sample measured before the analyte?

Accepted Answer

To correct for absorbance due to the solvent and cuvette.

Question 5

Which region of the electromagnetic spectrum is typically used for molecular vibrational analysis in FTIR spectroscopy?

Accepted Answer

Infrared

Question 6

A 31.7 g hummingbird flies at 30.0 mi/hr. What is its de Broglie wavelength? (Use $$\lambda = \frac{h}{mv}$$, $$h = 6.626 	imes 10$$^{-34}$$ J·s, 1$ mi/hr = 0.447$ m/s)

Accepted Answer

$$1.56 	imes 10$$^{-36}$$ m

Question 7

Which of the following is a requirement for a molecular vibration to be IR active?

Accepted Answer

It must result in a change in the molecule's net dipole moment.

Question 8

In atomic absorption spectroscopy (AAS), what is the primary purpose of the hollow cathode lamp?

Accepted Answer

To provide light at the specific wavelength absorbed by the analyte.

Question 9

Which of the following is a limitation of flame atomic absorption spectroscopy (FAAS)?

Accepted Answer

It requires flammable gases for operation.

Question 10

A sample is analyzed by graphite furnace AAS. Which advantage does this technique have over flame AAS?

Accepted Answer

It allows for unattended overnight operation.

Question 11

Which of the following best explains the Stokes shift observed in fluorescence spectroscopy?

Accepted Answer

The emission wavelength is longer due to energy loss during vibrational relaxation.

Question 12

Which process is responsible for the emission of light in atomic emission spectroscopy (AES)?

Accepted Answer

Relaxation of excited electrons to lower energy levels

Question 13

A solution absorbs 60% of incident light at a given wavelength. What is its transmittance ($$T) $$and absorbance ($$A$$)?$$
$$
$$A = -\log T$$

Accepted Answer

$$T = 0.40,\ A = 0.398$$

Question 14

Which of the following is NOT a component of a typical FTIR spectrometer?

Accepted Answer

Monochromator

Question 15

Which statement best describes the difference between atomic and molecular spectra?

Accepted Answer

Molecular spectra involve electronic, vibrational, and rotational transitions, making them more complex.

Question 16

In the Beer-Lambert Law, which variable is directly proportional to the concentration of the absorbing species?$$
$$
$$A = \varepsilon b c$$

Accepted Answer

$$A ($$Absorbance)

Question 17

Which of the following is a real-world application of ion-selective electrodes?

Accepted Answer

Measuring the pH of blood in medical diagnostics

Question 18

Which type of interference is observed when two waves of the same frequency and phase combine?

Accepted Answer

Constructive interference

Question 19

Which of the following is a limitation of graphite furnace atomic absorption spectroscopy (GFAAS)?

Accepted Answer

It requires expensive consumables such as graphite tubes.

Electroanalytical and Spectroscopic Methods in Analytical Chemistry

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