Atype of spectroscopy used to analyze pigments in a painting is:
a. ultraviolet absorption
b. microwave emission
c. x-ray fluorescence
d. infrared absorption
e. color phosphorescence

I would say the answer is D

Paint samples received by forensic laboratories are usually in the form of small chips or smears. Infrared (IR) spectroscopy is one of the most commonly used tools available for the analysis of these types of samples and serves as a staple comparative technique in the assessment of whether or not a questioned sample could have come from a suspected object

The most direct way to probe the vibrational frequencies of a molecule is through infrared spectroscopy. This is because vibrational transitions typically require an amount of energy that corresponds to the infrared region of the spectrum. Raman spectroscopy, which typically uses visible light, can also be used to directly measure vibration frequencies.

d) Infrared absorption

Explanation:

Spectroscopy involves the study of the interaction of electromagnetic radiation with matter.  The electromagnetic spectrum is essentially a composite of photons of different wavelengths and frequencies; from the low wavelength gamma rays to the high wavelength radio waves.

The pigments in a painting are organic compounds which can be easily identified via Infrared spectroscopy. When a beam of infrared light (photons in the 700 nm-1000 nm of the electromagnetic spectrum) is passed through the painting, photons of particular wavelengths or energy which are in resonance with the molecular vibrations of the pigment molecules get absorbed whereas the rest of the IR radiation is reflected and directed onto a detector. A plot intensity of the reflected IR light vs wavelength corresponds to the IR spectrum which is unique to a particular chemical substance. Thus, various pigments in a painting that have IR active features can be identified by this method.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.