SPSC CHEMISTRY 25 YEARS PAST PAPERS
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
دو سو بیس ینیم پر انو کے جذب کی پیمائش کے لئے کس قسم کے نمونہ کیویٹ کو استعمال کیا جانا چاہئے؟
Glass
Quartz
Plastic
None of these
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Explanation
Quartz cuvettes are used for UV measurements because they are transparent to UV light, including 220 nm. Glass and plastic cuvettes absorb UV light below 300 nm .
میسٹلین کا آئی یو پی اے سی نام ______ ہے؟
1,2,3-Trimethylcyclohexane
1,2,4-Trimethylbenzene
1,3,5-Trimethylbenzene
None of these
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Explanation
Mesitylene consists of a benzene ring with three methyl (-CH₃) groups at positions 1, 3, and 5. It is an aromatic hydrocarbon. It is commonly used as a solvent and in chemical synthesis.
مندرجہ ذیل میں سے کون سے جوہری میں اضافی الیکٹرانوں پر قبضہ کرنے کا سب سے بڑا رجحان ہے؟
S
F
Cl
None of these
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Explanation
Fluorine has the highest electronegativity, making it more likely to capture an additional electron . Fluorine is the smallest atom with the greatest effective nuclear charge, which strongly attracts electrons.
مندرجہ ذیل میں سے کون سا منتقلی دھات کا ممبر نہیں ہے؟
The titanium family
The scandium family
The beryllium family
None of these
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Explanation
The beryllium family is not considered a transition metal family. Beryllium is an alkaline earth metal. The titanium, scandium, and iron families are part of the transition metals.
2nd period, VA group
3rd period, VIIA group
5th period, IIIA group
None of these
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Explanation
The electronic configuration 3s² 3p⁵ corresponds to the element Chlorine (Cl). Chlorine is in the 3rd period and VIIA group (Group 17) of the periodic table.
رد عمل کا انفالپی ایک ہی ہے چاہے رد عمل ایک یا کئی مراحل میں ہوتا ہے۔ یہ کے طور پر جانا جاتا ہے؟
First law of thermodynamics
Hess's law
Boyle's law
None of these
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Explanation
Hess's law states that the total enthalpy change of a reaction is independent of the pathway taken. It follows the principle of energy conservation in thermodynamics.
3.7g in 100 cm^3
7.3g in 100 cm^3
36.7g in 100 cm^3
None of these
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Explanation
To find the mass of HCl, we need to calculate the number of moles of HCl in 100 cm^3 (or 0.1 L) of 2M HCl solution, and then multiply it by the molar mass of HCl.
Number of moles = Molarity × Volume (in liters)
= 2 M × 0.1 L
= 0.2 mol
Molar mass of HCl = 36.5 g/mol
Mass of HCl = Number of moles × Molar mass
= 0.2 mol × 36.5 g/mol
= 7.3 g
رامان سپیکٹرا _____ میں حاصل کیا جاسکتا ہے؟
UV and Visible region
IR and Visible region
IR and Microwave region
None of these
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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.
