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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
کوویلنٹ بانڈ کیسے بنتا ہے؟
- Sharing of electron
- Gain of an electron
- Transfer of electron
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- A covalent bond forms when atoms share electrons.
- It usually occurs between non-metals.
- Sharing helps atoms achieve stable electron configuration.
- No transfer of electrons occurs.
- Therefore, it is based on electron sharing.
Last verified on 12-04-2026
بانڈ انرجی، بانڈ لینتھ اور بانڈ آرڈر یہ تینوں کس چیز کو بیان کرتے ہیں؟
- Strength of a bond
- Polarity of a bond
- Energy of a bond
- None of these
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Explanation
- Bond energy, length, and order describe how strong a chemical bond is.
- Higher bond energy → stronger bond.
- Shorter bond length → stronger bond.
- Higher bond order → stronger bond.
- All three parameters indicate bond strength.
Last verified on 12-04-2026
- Zero order
- Half order
- 1st order
- None of these
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Explanation
Rate ∝ ^n
If × 4 → Rate × 2:[Reactant]
4ⁿ = 2 → n = 1/2
Last verified on 12-04-2026
- -4
- 4
- -2
- None of these
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Explanation
- Carbon is a tetravalent element.
- It forms 4 covalent bonds in most compounds.
- In C₂H₆O (ethanol or dimethyl ether), carbon still makes 4 bonds.
- Valency is based on bonding capacity, not charge here.
- So, carbon’s valency remains 4.
Last verified on 12-04-2026
- 80 KJ
- 75 KJ
- 40 KJ
- None of these
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Explanation
Use the first law of thermodynamics: ΔU = Q + W
Sign convention:
Heat added _to_ system: Q = +20 kJ
Work done _on_ system: W = +60 kJ
ΔU = 20 + 60 = 80 kJ
Last verified on 12-04-2026
وہ دو اجزاء جنہیں طبعی طریقوں سے الگ کیا جا سکتا ہو، انہیں کیا کہتے ہیں؟
- Mixture
- Substance
- Element
- None of these
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Explanation
- When two or more substances are physically combined, they form a mixture.
- In a mixture, components retain their properties.
- They can be separated by physical methods like filtration or evaporation.
- No chemical bonding is involved.
- Therefore, such elements form a mixture.
Last verified on 12-04-2026
کون سا عنصر گروپ 17 سے تعلق رکھتا ہے؟
- Sodium
- Magnesium
- Chlorine
- None of these
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Explanation
- Group 17 elements are called halogens.
- They are highly reactive non-metals.
- These elements readily gain one electron.
- Chlorine is a member of Group 17.
Last verified on 12-04-2026
ایک مول میں کتنی مقدار ہوتی ہے؟
- 6.02 × 10²³
- 6.02 × 10¹³
- 6.02 × 10³³
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- A mole is a unit used in chemistry.
- It represents a very large number of particles.
- This number is called Avogadro’s number.
- 1 mole contains 6.02 × 10²³ particles.
- These particles can be atoms, molecules, or ions.
Last verified on 12-04-2026
کسی ایکو سسٹم میں نیا شکاری داخل کرنے کا سب سے ممکنہ ماحولیاتی اثر کیا ہوگا؟
- Decrease in its prey population
- Increase in its prey population
- Rapid increase in predator reproduction rate
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- A new predator increases predation pressure on prey.
- This leads to a decrease in prey population.
- More prey get hunted and fewer survive.
- Ecosystem balance may temporarily change.
- So, prey population is most directly affected.
Last verified on 12-04-2026
پیپسن مضبوط تیزابی حالات میں بہترین کام کرتا ہے۔ اس سے کیا ظاہر ہوتا ہے؟
- It can function over a wide range of pH levels
- It functions best under a specific pH ranges
- It is activated by alkaline conditions
- None of these
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Explanation
- Pepsin is a digestive enzyme in the stomach.
- It works best in strong acidic conditions (low pH).
- This means enzymes have an optimum pH range.
- Outside this range, activity decreases.
- So, it does not work equally at all pH levels.
Last verified on 12-04-2026
