To improve a chromatographic separation, you must A. Increase the number of theoretical plates on the column. B. Increase the height of the theoretical plates on the column. C. Increase both the number and the height of the theoretical plates on the column. D. Decrease both the number and the height of the theoretical plates on the column

To improve a chromatographic separation, you must A. Increase the number of theoretical plates on the column. B. Increase the height of the theoretical plates on the column. C. Increase both the number and the height of the theoretical plates on the column. D. Decrease both the number and the height of the theoretical plates on the column
by

1 Answer

Answer :

Increase the number of theoretical plates on the column
by

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The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will (A) Increase (B) Decrease (C) Remain same (D) Depend on saturated boiling point; may increase or decrease

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As per USP, number of theoretical plates for an analyte peak in HPLC must be? A. More than 2000 B. More than 1000 C. More than 3000 D. More than 4000

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Steam distillation is used to (A) Reduce the number of plates (B) Avoid thermal decomposition of a component (C) Increase the efficiency of separation (D) Increase the total pressure of distillation

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Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

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At __________ reflux, theoretical number of plates in a distillation coloumn is calculated using Fenske-Underwood equation. (A) Operating (B) Total (C) Minimum (D) Maximum permissible

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Pick out the correct statement. (A) Higher hold up of the solid in the rotary dryer results in better exposure of the solids to the gas (B) The 'Hatta number' is important in problems involving gas absorption without chemical reaction (C) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion (D) Total reflux in case of distillation operation requires infinite number of plates for a binary system separation

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Fenske equation for determining the minimum number of theoretical stages in distillation column holds good, when the (A) Relative volatility is reasonably constant (B) Mixture (to be separated) shows negative deviation from ideality (C) Mixture (to be separated) shows positive deviation from ideality (D) Multi-component distillation is involved

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In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B

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In McCabe-Thiele method of theoretical plate calculation for a distillation column, the operating lines of stripping and rectifying sections coincide with the diagonal at __________ reflux. (A) Total (B) Minimum (C) Operating (D) Maximum permissible

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Reboiler is considered as one theoretical plate, because (A) Of the assumption that vapour and liquid leaving the reboiler are in equilibrium (B) Vapour is recycled to the column (C) Reboiler itself contains one plate (D) None of these

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For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause __________ plate requirement. (A) No change in theoretical (B) Marginal decrease in the number of (C) Major decrease in the number of (D) None of these

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Hypersecretion of growth hormone in adults does not cause further increase in height, because (a) epiphyseal plates close after adolescence (b) bones loose their sensitivity to growth hormone in adults (c) muscle fibres do not grow in size after birth (d) growth hormone becomes inactive in adults.

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Last Answer : (a) epiphyseal plates close after adolescence

Hypersecretion of Growth Hormone in adults does not cause further increase in height, because: (1) Epiphyseal plates close after adolescence. (2) Bones loose their sensitivity to Growth Hormone in adults. (3) Muscle fibres do not grow in size after birth. (4) Growth Hormone becomes inactive in adults.

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