Chemistry MCQs
Topic Notes: Chemistry
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
91
Which nitrogen oxide is commonly referred to as laughing gas?
Answer:
N2O
Nitrous oxide (N2O) is widely known as laughing gas. It is a colorless, non-flammable gas with a slightly sweet odor and taste. It is frequently used in medical and dental procedures as an anesthetic and analgesic agent, and it is known for its euphoric effects when inhaled.
92
Which of these gases diffuse more quickly than oxygen ?
Answer:
NO
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.
93
In O2 each oxygen atom is hybridized_________________?
Answer:
sp2
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.
94
Oxygen does not react with all except_________________?
Answer:
Metals
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.
95
Because of its ability to combine with both oxygen and nitrogen aluminium metal is used_____________?
Answer:
To remove air bubbles from molten metal
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.
96
The most common material used in making solar cells is
Answer:
Silicon
Silicon is, by far, the most common semiconductor material used in solar cells, representing approximately 95% of the modules sold today. It is also the second most abundant material on Earth (after oxygen) and the most common semiconductor used in computer chips.
97
The percentage of nitrogen in urea is about:
Answer:
46.6
The percentage of nitrogen in urea (CH4N2O) is 46.6%. To calculate the percentage of nitrogen in urea, we can use the following formula: (mass of nitrogen / mass of urea) * 100% The mass of nitrogen in urea is 28 g/mol, and the mass of urea is 60 g/mol. Therefore, the percentage of nitrogen in urea is: (28 g/mol / 60 g/mol) * 100% = 46.6%
98
What fertilizer supplies both nitrogen and phosphorus to plants?
Answer:
diammonium phosphate
Diammonium phosphate (DAP) is a complete fertilizer containing both nitrogen (N) and phosphorus (P), essential nutrients for plant growth. Urea provides nitrogen, calcium superphosphate provides phosphorus, and potassium nitrate provides potassium.
99
When magnesium ribbon is burnt in presence of air, it forms
Answer:
White flame
When magnesium ribbon is burnt in the air, it combines with oxygen to form white powder magnesium oxide MgO with the release of heat and light. It forms a white powder of magnesium oxide. Magnesium gives up two electrons to oxygen atoms to form this powdery product.
100
What is the source of oxides of nitrogen?
Answer:
Powerstations & industries using fossil fuels and exhaust fumes of motor vehicles
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.