What is the atomic number of aluminium?
13
26
14
12
Correct answer is A
The atomic number of an element is the number of protons in the nucleus of an atom of that element. The atomic number of aluminium is 13, which means it has 13 protons in its nucleus.
Which type of salt is found in antacid medications and is used to relieve heartburn and indigestion?
Aluminum chloride
Magnesium chloride
Sodium chloride
Calcium chloride
Correct answer is B
Magnesium chloride is used in antacid medications to relieve heartburn and indigestion. It helps neutralize excess stomach acid.
When anhydrous cobalt chloride paper is exposed to water, what color change is observed?
From pink to blue
From white to blue
From blue to white
From blue to pink
Correct answer is D
nhydrous cobalt chloride paper is blue in the absence of water. However, when it comes into contact with water, it undergoes a color change to pink due to the formation of hydrated cobalt chloride.
What is the valency of an element with the electronic configuration 2, 8, 7?
7
1
2
3
Correct answer is B
The valency of an element is determined by the number of electrons it gains or loses to achieve a stable electron configuration. For an element with the electronic configuration 2, 8, 7, the outermost shell (valence shell) has 7 electrons. To achieve stability, it needs 1 more electron to fill the outermost shell, so its valency is 1.
Which of the following methods is commonly used to remove suspended impurities from water?
Fluoridation
Chlorination
Filtration
Distillation
Correct answer is C
Filtration is commonly used to remove suspended impurities, such as dirt, sand, and other particles, from water. In this process, water is passed through a filter medium that traps the solid impurities while allowing the clean water to pass through.