UAF ENTRY TEST PAST PAPER 23-07-2017
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
صفر آرڈر کے رد عمل کے لئے شرح مستقل کی اکائی _____ ہے؟
dm⁻³ s⁻¹
mole dm⁻³ s⁻¹
dm⁻³ mole⁻¹ s⁻¹
mole s⁻¹
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Explanation
The correct unit of the rate constant for a zero-order reaction is mol dm⁻³ s⁻¹ or mol L⁻¹ s⁻¹.
Zero-order reactions have a rate that is independent of the concentration of reactant s.
Therefore, the rate constant (k) will have the same units as the reaction rate,
Which are typically expressed as concentration per unit time.
In this case, since the concentration unit is mol/L (or mol/dm³),
The rate constant unit become s mol dm⁻³ s⁻¹ or mol L⁻¹ s⁻¹.
معیاری انفالپی تبدیلی _____ پر ماپا جاتا ہے؟
298°K
273°C
273°K
373°K
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Explanation
Standard enthalpy change is measured at a defined pressure of 101 kPa (or 1 bar, according to Testbook.com) and a temperature of 298 K (25°C).
7
>7
<7
1
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Explanation
The pH of a mixture of CH₃COONa (sodium acetate) and CH₃COOH (acetic acid) is C. <7.
This mixture forms a buffer solution, where the weak acid (CH₃COOH)
Its conjugate base (CH₃COO-) is present together, resulting in a pH that is less than 7 (acidic) but not extremely so
ایک مثالی گیس کی کثافت کا حساب فارمولا ______ کے ذریعہ کیا جاسکتا ہے؟
d=nRT
d=PM/RT
d= m/M RT
d=PV/M
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Explanation
The formula for calculating the density of an ideal gas is d = PM/RT, where:
d: is the density of the gas P: is the pressure of the gas M: is the molar mass of the gas R: is the ideal gas constant T: is the temperature of the gas in Kelvin
The ideal gas law is expressed as PV = nRT, where 'n' is the number of moles.
Density (d) is mass (m) divided by volume (V), so d = m/V.
We can relate the number of moles (n) to mass (m) and molar mass (M) using n = m/M.
Substituting this into the ideal gas law, we get PV = (m/M)RT.
Rearranging the equation to solve for density (d = m/V), we get d = PM/RT.
آکسائڈائزنگ ایجنٹ مضبوط ، _____ زیادہ ہے؟
Oxidation potential
Redox potential
Reduction potential
None of these
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Explanation
A strong oxidizing agent has a greater Reduction potential.
An oxidizing agent readily accepts electrons, which corresponds to a high reduction potential.
A higher reduction potential indicates a greater tendency for a substance to be reduced (gain electrons) and thus act as an oxidizing agent.
مثالی طرز عمل سے گیس کا انحراف زیادہ سے زیادہ _____ ہے؟
-100°C and 5 atm
-10°C and 2 atm
-10°C and 5 atm
None of these
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Explanation
Deviation from ideal gas behavior is maximum at low temperatures and high pressures due to intermolecular forces and finite volume of gas molecules. -10°C (low temp) and 5 atm (high pressure) causes maximum deviation from ideal gas behavior.
آئنک ٹھوس خصوصیات _____ کی طرف سے ہیں؟
Good conductivity
High vapour pressure
Solubility in polar solvents
None of these
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Explanation
Ionic solids (like NaCl) are generally soluble in polar solvents (like water) due to strong ion-dipole interactions. They are poor conductors in solid state but conduct when molten or dissolved, and they have low vapor pressure .
n = 2, I = 0
n = I, 1 = 0
n = 1, I = 2
n = 2, I = 1
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Explanation
For 2p orbitals , the principal quantum number (n) is 2.
The azimuthal quantum number (l) for a p-orbital is 1.
So, n = 2, l = 1 is correct.
سوکروز کو _____ نامی انزائم کیٹیلسٹ کے ذریعہ گلوکوز اور فریکٹوز میں تبدیل کیا جاتا ہے؟
Invertase
Maltase
Urease
Zymase
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Explanation
The enzyme that converts sucrose into glucose and fructose is called invertase
It is also known as sucrase or beta-fructofuranosidase.
This process is known as hydrolysis, where water is used to break the glycosidic bond between glucose and fructose in sucrose.
ایک سے زیادہ کرسٹل شکلوں میں کسی عنصر کا وجود ______ کے نام سے جانا جاتا ہے؟
Isotropy
Anisotropy
Entropy
Allotropy
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Explanation
The phenomenon where a chemical element exists in multiple crystalline forms is called allotropy
Allotropy refers to the ability of an element to exist in two or more different forms in the same physical state.
This is different from polymorphism, which is a broader term referring to any substance ( not just elements) that can exist in multiple crystalline forms.
