A. p-block
B. s-block
C. d-block
D. f-block
Correct Answer: D. f-block
Lanthanoids form part of the series of chemical elements comprising the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through the lutetium. They are a part of the f-block of elements in the periodic table.
A. s-block
B. p-block
C. d-block
D. f-block
Correct Answer: B. p-block
The p-Block Elements comprise those belonging to Group 13 to 18 and these together with the s-Block Elements are called the Representative Elements or Main Group Elements. The 18th group i.e. the last group of the p-block elements is the noble gas group.
A. Adding antioxidants to the food
B. Storing food at low temperature
C. Replace the air with nitrogen in the packing material
D. All of the above
Correct Answer: D. All of the above
When food containing fats and oils are exposed to the atmosphere, the oxidation of fat and oil occurs, this is called as Rancidity.
A. becquerel
B. curie
C. candela
D. henry
Correct Answer: A. becquerel
The SI unit for activity is becquerel, named after the discoverer of radioactivity, Henry Becquerel. The c.g.s unit of activity is curie.
A. It is an alloy of Nickel, Tin, and Zinc
B. It is an alloy of Bismuth, Copper, and Palladium
C. It is an alloy of Palladium, Tin, and Lead
D. It is an alloy of Bismuth, Tin, and Lead
Correct Answer: D. It is an alloy of Bismuth, Tin, and Lead
Rose metal is an alloy of Bismuth, Tin, and Lead. It’s a fusible alloy with a low melting point commonly used for soldering.
A. Gypsum
B. Plaster of Paris
C. Chloroform
D. Limestone
Correct Answer: B. Plaster of Paris
Plaster of Paris is the common name of calcium sulfate hemihydrate because half molecule of water is attached with calcium sulfate. The chemical formula of the plaster of Paris is CaSO4.1/2H2O.
A. it increases
B. it decreases
C. it is the same for all
D. None of these
Correct Answer: B. it decreases
The ionization enthalpies of the alkali metals are considerably low and decrease down the group from Li to Cs.
A. it increases
B. it decreases
C. it remains constant
D. None of these
Correct Answer: A. it increases
The atomic and ionic radii of alkali metals increase on moving down the group i.e., they increase in size while going from Li to Cs.
A. Silver iodide
B. Potassium nitrate
C. Ammonium chloride
D. Sodium phosphate
Correct Answer: B. Potassium nitrate
Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpeter. It is also known as “Chinese snow”. Major uses of potassium nitrate are in fertilizers, rocket propellants, and fireworks.
A. Avogadro
B. Dalton
C. Rutherford
D. Niels Bohr
Correct Answer: B. Dalton
The given principle is one of the postulates of Dalton’s atomic theory given in 1803 by John Dalton. The postulates of Dalton’s atomic theory are as follows:
1. Elements consist of indivisible small particles (atoms).
2. All atoms of the same element are identical; different elements have different types of atom.
3. Atoms can neither be created nor destroyed.