SPSC 25 YEARS PAST PAPERS 2001 TO 2026
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
رامان سپیکٹرا _____ میں حاصل کیا جاسکتا ہے؟
- UV and Visible region
- IR and Visible region
- IR and Microwave region
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Raman spectra are obtained using visible and infrared (IR) light due to inelastic scattering of photons.It is commonly used for molecular structure analysis and vibrational mode identification.
مندرجہ ذیل میں سے کون سا آرگومیٹالک مرکب ہے؟
- Pb(NO₃)₂
- LiN(CH₂)₂
- Pb(C₆H₅)₂
- None of these
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Explanation
Organometallic compounds contain a metal-carbon bond where the carbon is part of an organic group.Lead diphenyl (Pb(C₆H₅)₂) is an organometallic compound as it has Pb–C bonds.
- Negative and Large
- Zero
- Negative and Small
- None of these
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Explanation
A system is at equilibrium when ΔG° (Gibbs free energy change) = 0.At this point, there is no net change in the system.It means the forward and reverse reactions occur at the same rate.
- 85.8mg/L, 86.7mg/L, 88.85mg/L, 87mg/L
- 107.5mg/L, 105 mg/L, 109mg/L, 110.5mg/L
- 102mg/L, 103mg/L, 102.7mg/L, 101.5mg/L
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
85.8 mg/L, 86.7 mg/L, 88.85 mg/L, 87 mg/L
These values are far from the accepted value (105 mg/L), so they have low accuracy.
They are very close to each other, so they have high precision.
Conclusion: Low accuracy and high precision.
- Cu^2+, Zn^2+
- Bi^3+, Sn^4+
- Al^3+, Hg^2+
- None of these
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Explanation
H₂S in dilute HCl is used to separate metal ions based on their solubility as sulfides.Bi³⁺ and Sn⁴⁺ do not separate easily.Because they both form insoluble sulfides under similar conditions.
برقی مقناطیسی تابکاری کا ماخذ جو آلے کے جوہری جذبوں میں استعمال ہوتا ہے اسپیکٹرو فوٹومیٹر _____ ہے؟
- Deuterium lamp
- Tungsten lamp
- Hallow cathode lamp
- None of these
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Explanation
In atomic absorption spectrophotometry, the hollow cathode lamp is used as the source of electromagnetic radiation.It emits specific wavelengths corresponding to the element being analyzed.It providing highly sensitive absorption measurements.
جب کسی نیوکلیوفائل کا نیوکلیوفیلیسیٹی ، کسی ایٹم میں شامل ہوتا ہے تو توقع سے زیادہ پایا جاتا ہے _____ اثر کے نام سے جانا جاتا ہے؟
- Gamma
- Beta
- Alpha
- None of these
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Explanation
When the nucleophilicity of a nucleophile, joined to an atom, is found to be greater than expected, it is referred to as the beta effect.The beta effect occurs due to the inductive or hyperconjugative influence from neighboring atoms.
مندرجہ ذیل میں سے کون سا بانڈ آئی آر میں سب سے مضبوط جذب دکھائے گا؟
- Sulfur-hydrogen
- Nitrogen-hydrogen
- Oxygen-hydrogen
- None of these
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Explanation
O-H bonds show the strongest IR absorption due to their high polarity and strong hydrogen bonding.They typically absorb around 3200–3600 cm⁻¹ in the IR spectrum.
مندرجہ ذیل میں سے کون سا ڈوپول لمحہ نہیں ہے؟
- Trans-1,2-Dichloroethene
- 1,1-Dichloroethene
- 1,2-Dichloroethene
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
In trans-1,2-dichloroethene, the dipoles of the two Cl atoms cancel out due to their opposite positions.This results in zero net dipole moment, making it a non-polar molecule.
- 0.65 T
- 0.75 T
- 0.56 T
- None of these
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Explanation
Transmittance (T) is calculated using the formula: T = 10^(-A).For A = 0.25, T = 10^(-0.25) ≈ 0.56 (or 56%).
