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- Question
Which one of the following elements cannot be detected by "Lassaigne's test"?
Options- A. I
- B. Cl
- C. S
- D. F
- Correct Answer
- F
ExplanationThe sodium fusion test, or Lassaigne's test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens, nitrogen, and sulphur, in an organic compound. It was developed by J. L. Lassaigne.Silver fluoride is soluble in water and does not precipitate and thus this method cannot be used for detection of fluorine.
- 1. Match List -I with List -II and select the correct answer using the code given below the Lists : List -I List-II (Compound/Molecule) (Shape of Molecule) A. CH3F 1. Trigonal planar B. HCHO 2. Tetrahedral C. HCN 3. Trigonal pyramidal D. NH3 4. Linear
Options- A. 2 4 1 3
- B. 2 1 4 3
- C. 3 4 1 2
- D. 3 1 4 2 Discuss
- 2. Which one of the following statements is correct?
Options- A. The oxidation number for hydrogen is always zero.
- B. The oxidation number for hydrogen is always + 1.
- C. The oxidation number for hydrogen is always -1.
- D. Hydrogen can have more than one oxidation number. Discuss
- 3. Highest percentage of carbon is found in which form of coal?
Options- A. Anthracite
- B. Bituminous
- C. Peat
- D. lignite Discuss
- 4. Which one of the following elements does not form solid hydrogen carbonate?
Options- A. Sodium
- B. Potassium
- C. Caesium
- D. Lithium Discuss
- 5. Bee sting contains________________
Options- A. An acidic liquid
- B. a salt solution
- C. an alkaline liquid
- D. a corrosive liquid Discuss
- 6. In which of the following, functional group isomerism is not possible?
Options- A. Alcohols
- B. Aldehydes
- C. Alkyl halides
- D. Cyanides Discuss
- 7. Which one of the following statements is not correct?
Options- A. Fischer projection represents the molecule in an eclipsed conformation
- B. Newman projection can be represented in eclipsed, staggered and skew conformations
- C. Fischer projection of the molecule is its most stable conformation
- D. In Sawhorse projections, the lines are inclined at an angle of 120 deg to each other. Discuss
- 8. Which of the following is most important for absorption of heat radiated from the Sun as well as from the Earth?
Options- A. Carbon dioxide
- B. Oxygen
- C. Carbon monoxide
- D. Nitrogen Discuss
- 9. What are isobars?
Options- A. Elements with same atomic number but different mass number
- B. Elements with different atomic number but same mass number
- C. Elements with different atomic number and different mass number
- D. Elements with same atomic number and same mass number Discuss
- 10. Which of the following pairs is INCORRECT? I. Haematite : Iron II. Pitchblende : Copper III. Monazite : Thorium
Options- A. Only I
- B. Only II
- C. Only I and Only II
- D. Only I and Only III Discuss
Chemistry problems
Search Results
Correct Answer: 2 1 4 3
Explanation:
HCHO: The carbon and and the oxygen are bonded through a double bond which counts as "one electron pair". Hence the molecule has three electron pairs and is trigonal planar.
Correct Answer: Hydrogen can have more than one oxidation number.
Explanation:
Hydrogen has two possible oxidation numbers: +1 and -1.
-1 in case of hydrides.
Correct Answer: Anthracite
Correct Answer: Lithium
Explanation:
Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate) is the inorganic compound with the chemical formula KHCO3. It is a white solid
Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder.
LiHCO3 is found in solution form while rest alkali metals hydrogen carbonates are solid due to the anomalous properties of Li and its diagonal relationship with the Mg.
Correct Answer: An acidic liquid
Correct Answer: Alkyl halides
Explanation:
The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of chemical compounds derived from alkanes containing one or more halogens.Halogens can?t form more than one bond in the context of common organic compounds and can?t form multiple bonds to carbon.
Correct Answer: Fischer projection of the molecule is its most stable conformation
Explanation:
Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry.A Fischer projection always uses an eclipsed conformation. A Newman diagram can represent either an eclipsed conformation or a staggered conformation or a skew conformation.
Correct Answer: Carbon dioxide
Correct Answer: Elements with different atomic number but same mass number
Correct Answer: Only II
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