- 10%
- 15%
- 18%
- 21%
- d
-
Normal air contains about 21% oxygen and 78% nitrogen.
Oxygen is essential for combustion and human respiration.
Chemistry MCQs
All Chemistry MCQs are included in this section of ETEST Academy’s Website. All Chemistry MCQs are completely solved with detailed answers. All Chemistry MCQs are taken from different Current & Past Papers. Our team updates ETEST Website on daily basis.
What are the three elements of the fire triangle?
- Water, Fuel, Heat
- Oxygen, Gas, Smoke
- Smoke, Heat, Water
- Fuel, Oxygen, Heat
- d
-
Fire occurs when fuel, oxygen, and heat combine.
Removing any one of these elements can stop or control the fire.
The fat soluble vitamin are stored in body fat and may therefore accumulate in quantities ____
- That can be toxic
- Can be Toxic
- They can be toxic
- Can they be toxic
- a
-
Fat soluble vitamins are Vitamin A, Vitamin D, Vitamin E and Vitamin K but too much quantity of these vitamins can be toxic.
Pure limestone is called:
- Calcium Sulphate
- Calcium Carbonate
- Aluminum Oxide
- None of these
- b
-
Chemical formula of Calcium Carbonate is CaCO3.
It is usually found in White, Gray or Light Brown color.
It is used in buildings, roads and bridges.
It is also used in forming to reduce the soil acidity.
The water molecule is amphoteric (it acts both as an acid and base). It is the perfect medium for biochemical relations occurring in cells. It acts as:
- An Alkali
- An Acid
- A Solvent
- A steroid molecule
- c
-
Amphoteric means a substance that can act both as an acid and as a base.
The molar volume of CO2 gas is 22.4 dm3 at:
- 25 C and 2 atm
- 0 K and 1 atm
- 25 K and 0.5 atm
- 0 C and 1 atm
- d
-
1ATM (atmosphere) is a normal air pressure at sea level.
1ATM is equal to 760 Torr.
In simple words atm is unit of Pressure.
The space (volume) that 1 mole of a gas takes is called molar volume.
Red lead (Sandur) is:
- Pb3O4
- PbO4
- PbO2
- Pb2O
- a
-
Sandur dissolves in acids.
Sandur is toxic because it contains lead.
The electronic configuration of Na is:
- 1s2,2s2,2p6,3s2,3p6,4s1
- 1s2,2s2,2p6,3s1
- 1s2,2s2,2p6,3s2
- 1s2,2s2,2p6,3s2,3p6,4s2
- b
-
Na is chemical formula of Sodium.
Its atomic number is 11.
It falls in Group-1 of periodic table.
Its only soluble isotope.
پانی کا کیمیکل فارمولا کیا ہے؟
- H2O
- H2SO4
- NaCl
- ان میں سے کوئی نہیں
- a
-
پانی کے کیمیکل فارمولا میں ہائیڈروجن کے دو ایٹم اور آکسیجن کا ایک ایٹم شامل ہے۔
گندھک کے تیزاب کا فارمولا ۔۔۔۔۔ ہے۔
- H3SO4
- H2SO4
- H5NH3
- ان میں سے کوئی نہیں
- b
-
گندھک کے تیزاب کا کیمیکل نام سلفیورک ایسڈ ہے۔
گندھک کا تیزاب ہائیڈروجن، سلفر اور آکسیجن کے کیمیکل ری ایکشن سے بنتا ہے۔
گندھک کے تیزاب کا مولر ماس 98.079 گرام /مولر ہے۔
گندھک کے تیزاب کا بوائلنگ پوائنٹ 337 ڈگری سینٹی گریڈ ہے۔