Forensic Chemistry and Toxicology Review Questions 1
Forensic Chemistry and Toxicology Review Questions 1
1. A substance yields a deep purple color with the Marquis reagent and a bright blue color with Simon’s reagent. Which substance is most likely present?
A. Heroin
B. Methamphetamine Hydrochloride (Shabu)
C. Cocaine
D. Marijuana
Answer: B
2. A victim's blood and internal organs exhibit a bright, cherry-red discoloration. This is a classic sign of lethal poisoning by which substance?
A. Cyanide
B. Arsenic
C. Carbon Monoxide
D. Mercury
Answer: C
3. Which non-destructive analytical instrument is best suited to determine the chemical composition, organic binders, and pigments of a microscopic paint flake?
A. Gas Chromatography-Mass Spectrometry (GC-MS)
B. Fourier Transform Infrared Spectroscopy (FTIR)
C. Atomic Absorption Spectroscopy (AAS)
D. Ultraviolet-Visible (UV-Vis) Spectroscopy
Answer: B
4. Which presumptive color test for blood uses a solution of phenolphthalein and hydrogen peroxide to produce a deep pink color?
A. Kastle-Meyer Test
B. Takayama Test
C. Teichmann Test
D. Benzidine Test
Answer: A
5. Alcohol is metabolized by the human body at a constant rate that is independent of its concentration in the blood. This metabolic process follows:
A. First-order kinetics
B. Zero-order kinetics
C. Michaelis-Menten clearance
D. Oxidative phosphorylation
Answer: B
6. Which chemical test reacts with the iron in hemoglobin to cause trace, invisible bloodstains to luminesce blue in the dark?
A. Precipitin test
B. Kastle-Meyer Test
C. Luminol Test
D. Hemastix Test
Answer: C
7. Which test uses rabbit antiserum to produce a visible precipitation line to determine if a blood sample is of human or animal origin?
A. Precipitin test
B. Kastle-Meyer Test
C. Luminol Test
D. Hemastix Test
Answer: A
8. Which rapid, field-ready presumptive test uses a plastic strip with a reagent pad that turns from yellow to green/blue in the presence of blood?
A. Precipitin test
B. Kastle-Meyer Test
C. Luminol Test
D. Hemastix Test
Answer: D
9. Which diagnostic screening test involves rubbing a stain with a swab, adding reduced phenolphthalein and hydrogen peroxide, and watching for an immediate deep pink color?
A. Precipitin test
B. Kastle-Meyer Test
C. Luminol Test
D. Hemastix test
Answer: B
10. Among the options below, which one is a specific confirmatory or species identification test rather than a presumptive test?
A. Precipitin test
B. Kastle-Meyer Test
C. Luminol Test
D. Hemastix test
Answer: A
11. Methanol poisoning primarily affects which organ?
A. Liver
B. Heart
C. Eyes
D. Kidneys
Answer: C. Eyes.
Household bleach contains hypochlorite. Mixing bleach with an acid can release chlorine gas, which can irritate or injure the eyes and respiratory system.
12. Which household chemical can produce toxic chlorine gas when mixed with acids?
A. Bleach
B. Vinegar
C. Baking Soda
D. Alcohol
Answer: A. Bleach.
Methanol is particularly toxic to the optic nerve, potentially causing visual disturbances and blindness. It also causes serious metabolic and neurological toxicity, so “eyes” is best understood as the characteristic target in this set of options.
13. Mercury poisoning primarily affects the:
A. Skin
B. Nervous system
C. Bones
D. Teeth
Answer: B.
Mercury poisoning can significantly affect the nervous system, including neurological and behavioral functions.
14. Which poisonous gas is colorless, odorless, and tasteless?
A. Chlorine
B. Carbon monoxide
C. Ammonia
D. Sulfur dioxide
Answer: B.
Carbon monoxide (CO) is colorless, odorless, and tasteless.
15. Which toxic substance is commonly associated with contaminated fish and seafood?
A. Cyanide
B. mercury
C. Acetone
D. Ethylene glycol
Answer: B.
Mercury, particularly methylmercury, can accumulate in contaminated fish and seafood.
16. Which poison interferes with the body's ability to use oxygen at the cellular level?
A. Lead
B. Cyanide
C. Mercury
D. Arsenic
Answer: B.
Cyanide interferes with cellular respiration, preventing cells from effectively using oxygen.
17. Which poison is commonly found in vehicle exhaust fumes?
A. Cyanide
B. Carbon monoxide
C. Mercury
D. Arsenic
Answer: B.
Vehicle exhaust can contain carbon monoxide, particularly from incomplete combustion.
18. Which poison has a characteristic bitter almond odor (not detectable by everyone)?
A. Lead
B. Cyanide
C. Methanol
D. Mercury
Answer: B.
Some cyanide compounds are associated with a bitter-almond odor, but not everyone can detect it genetically.
19. Which heavy metal poisoning is commonly associated with old paint and batteries?
A. Arsenic
B. Mercury
C. Lead
D. Copper
Answer: C.
Lead exposure is historically associated with old lead-based paint and some batteries.
20. Which toxic substance has historically been used in some pesticides and rodenticides?
A. Arsenic
B. Acetone
C. Ethanol
D. Ammonia
Answer: A.
Arsenic compounds have been used in some pesticides and rodenticides, although many modern products no longer contain arsenic.
21. Methanol poisoning primarily affects which organ?
A. Liver
B. Heart
C. Eyes
D. Kidneys
Answer: C.
Methanol poisoning can cause optic-nerve injury and visual impairment, potentially leading to blindness.
22. Which household chemical can produce toxic chlorine gas when mixed with acids?
A. Bleach
B. Vinegar
C. Baking soda
D. Alcohol
Answer: A.
Bleach can release toxic chlorine gas when mixed with acids such as vinegar. However, "acides" should be "acids."
23. Which test is commonly used as a preliminary test for the presence of blood by producing a pink color?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Hemastix test
Answer: B. Kastle-Meyer test
Explanation: The Kastle-Meyer test is a presumptive test for blood. In the presence of blood and hydrogen peroxide, phenolphthalein is oxidized and produces a pink color.
24. Which test is particularly useful for detecting possible bloodstains that are not readily visible to the naked eye?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Hemastix test
Answer: C. Luminol test
Explanation: Luminol is a presumptive test that can reveal possible traces of blood through chemiluminescence, producing a blue or blue-white glow in dark conditions.
25. Which test is used to determine whether a blood sample is of human origin?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Hemastix test
Answer: A. Precipitin test
Explanation: The precipitin test is a serological test used to determine whether a suspected bloodstain is human blood by detecting human-specific proteins through an antigen-antibody reaction.
26. Which test uses a reagent strip designed to detect the peroxidase-like activity associated with blood?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Hemastix test
Answer: D. Hemastix test
Explanation: Hemastix is a reagent strip commonly used as a presumptive test for blood. A positive reaction produces a characteristic color change due to the peroxidase-like activity of hemoglobin.
27. Which test is classified primarily as a confirmatory test for the presence of blood rather than a presumptive screening test?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Takayama test
Answer: D. Takayama test
Explanation: The Takayama test is a microcrystal test that can provide confirmatory evidence of blood by producing characteristic hemochromogen crystals. Kastle-Meyer, Luminol, and Hemastix are generally used as presumptive tests.
28. Which test is based on an antigen-antibody reaction involving species-specific proteins?
A. Precipitin test
B. Kastle-Meyer test
C. Luminol test
D. Hemastix test
Answer: A. Precipitin test
Explanation: The precipitin test is based on an antigen-antibody reaction. It is particularly useful in forensic serology for determining whether a suspected bloodstain is of human origin.
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