Doubtly
@Doubtly · Joined Feb 2021
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- N. Name the different types of Chromatography and explain the principles underlying them. There are two types of chromatography namely: Liquid chromatography ⇒ separate ions that are dissolved insolvent Gas chromatography ⇒ separa... 2
- M. List the properties of solvents which make them suitable for crystallization The properties of solvents which make them suitable for crystallization are The compound to be crystallized should be least or sparingly sol... 1
- L. Define a. Solvent extraction b. Distillation. Solvent extraction : it is ultimately a process of partitioning between two immiscible solvents, and for its optimization, it is necessary t... 2
- K. What is the difference between simple distillation and fractional distillation? Distillation Fraction distillation Simple distillation is used to separate liquids with boiling point gaps of at least 50 degrees. Fractiona... 1
- J. Define : a. Stationary phase b. Saturated solution Statioanry phase - Stationary phase and mobile phase arr terms related to chromatography. Phase on which the materials to be separated are s... 1
- I. Why should spotting of mixture be done above the level of mobile phase ? In thin-layer chromatography( TLC), the sample mixture should be spotted above the solvent level. It is because if the mixture gets in conta... 1
- H. Which properties of solvents are useful for solvent extraction? Organic compound must be more soluble in the organic solvent, than in water. Solvent should be immiscible with water and be able to form two... 1
- G. Give names of two materials used as stationary phase in chromatography. names of two materials used as stationary phase in chromatography. alumina silica gel 1
- F. What will happen if the upper outlet of the condenser is connected to the tap instead of the lower outlet? It is necessary to cool the condenser with cool water for proper functioning of condenser. If tap is connected to the upper outlet then jack... 2
- Identify the pair whose dimensions are equal The correct option is B. The dimensions of torque and work are equal. Both have dimensions as [ML²T⁻²] Explaination: Work (W) = F.s = Fs cos... 1
- Which of the following physical quantities is an axial vector? Correct option is d) Torque Concept :: Axial vectors are those vectors that represent rotational effect and act along the axis of rotation.... 1
- A rocket is fired vertically with a speed of 5 kms-1 from the earth’s surface. How far from the earth does the rocket go before returning to the earth The correct option is (a) 8.0 ×10⁶ m Video Explaination From physics galaxy https://youtu.be/nz4kjm8L6ZU This video not belong to Brainiak f... 1
- The position vector of a moving particle at time t is r=3i+4t^2j-t^3k .. Its displacement during the time interval t=1 s to t=3 s is Correct answer is 32j-26k Explaination:: r=3i+4t²j-t³k r_(t=1s)=3i+4j-k r_(t=3s)=3i+36j-27k Displacement = (r_(t=3s))-(r_(t=1s)) = 32j-26k 1
- If a unit vector is represented by 0.5i +0.8 j +ck then the value of 'c' is Correct option is b) √(0.11) Explaination:: The unit vector is given as A=0.5i +0.8 j +ck Magnitude of unit vector is always equal to 1 √((0... 1
- The area of the region bounded by the curve y = 2x – x2 and x – axis is Correct answer is 4/3sq.units Explaination:: Given curve is y =2 x-x² or (x-1)² =-(y-1) The curve cut the x -axis at (0,0) and (2,0) . there... 1
- The point on the curve 6y = x3 + 2 at which y – co-ordinate is changing 8 times as fast as x– co-ordinate is ______________ Correct answer is option A){4,11} 2
- The joint equation of bisectors of angles between lines x = 5 and y = 3 is ___________ Answer: B) x² - y² - 10x + 6y + 16 = 0 The lines x = 5 (vertical) and y = 3 (horizontal) are perpendicular and meet at (5, 3) . Their angle... 1
- Derivative of log (secθ + tanθ ) with respect to secθ at θ = π/4 is ____________ Answer: B) 1 Let u = log(secθ + tanθ) and v = secθ . Differentiate both with respect to θ . du/dθ = fracsecθtanθ + sec²θsecθ + tanθ The nume... 1