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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 7751. |
An organic compound 'A' is widely used to preserve the pickles and has a molecular formula C_(2)H_(4)O_(2). This compound reacts with ethanol to form a sweet smelling compound 'B'. Write the chemical equation for the reaction of 'A' with ethanol in the presence of acid. |
| Answer» Solution :`underset("Acetic acid (A)")(CH_(2)-COOH)+underset("ETHANOL")(HO-C_(2)H_(5))overset("Acid")tounderset("Ethyl ACETATE (B)")(CH_(3)COOC_(2)H_(5))+underset("Water")(H_(2)O)` | |
| 7752. |
An organic compound 'A' is widely used to preserve the pickles and has a molecular formula C_(2)H_(4)O_(2). This compound reacts with ethanol to form a sweet smelling compound 'B'. Identify the compound 'A'. |
| Answer» SOLUTION :COMPOUND A is acetic ACID `(CH_(3)COOH)`. | |
| 7753. |
An organic compound A is widely used as a preservative in pickles and has a molecularformula C_(2)H_(4)O_(2). This compound reacts with ethanol to form a sweet smelling compound B. (i) Identify the compound A. (ii) Write the chemical equation for its reaction with ethanol. (iii) Name the products formed. (iv) Name the process involved in the reaction. (v) How can we get back the compou A from B. |
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Answer» Solution :(i) `CH_(3)COOH` (ETHANOIC acid). (ii) `CH_(3)-COOH+C_(2)H_(5)OHoverset("Conc.H_(2)SO_(4))rightarrow` `CH_(3)COOC_(2)H_(5)+H_(2)O` (III) Ethyl ethanoate. (IV) ESTERIFICATION. (v) Through SAPONIFICATION reaction. |
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| 7754. |
An organic compound 'A' is widely used as a preservative in pickles and has a molecular formula C_(2)H_(4)O_(2). The compound reacts with ethanol in presence of an acid to form a sweet smelling compound 'B' (a) identify the compound 'A' (b) Write the chemical equation for its reaction with ethanol to form compound 'B' (c) How can you get 'A' back from 'B'? (d) Name the process and write the corresponding chemiacl equation. (e) Which gas is produced when compound 'A' reacts with washing soda? Write the chemical equation. |
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Answer» SOLUTION :(a) The compound 'A' with molecular formula `C_(2)H_(4)O_(2)` is ethanoic acid and it is used as preservative in pickles. (b) The SWEET smelling compound 'B' is an ester called ethanoic ethanoate.  (c) The co9mpound 'B' can be converted to 'A' by reacting with a dilute solution of HCl. (d) the process is known as ester hydrolysis. `CH_(3)COOC_(2)H_(5)+H_(2)Ooverset(H^(+))tounderset((A))(CH_(3)COOH)+C_(2)H_(5)OH` (E) `CO_(2)` gas is produced when compound (A) reacts with washing soda i.e., sodium carbonate. `underset((A))(2CH_(3)COOH)+Na_(2)CO_(3)to2CH_(3)COONa+H_(2)O+CO_(2)` |
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| 7755. |
An organic compound 'A' is widely used as a preservative and has the molecular formula C_(2)H_(4)O_(2). This compound reacts with ethanol to form a sweet smelling compound 'B'. (i) Identify the compound 'A'. (ii) Write the chemical equation for its reaction with ethanol to form compound 'B'. (iii) Name the process. |
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Answer» SOLUTION :(i) Acetic acid `(CH_(3)COOH)` is widely USED as a PRESERVATIVE. (ii) `CH_(3)COOH` REACTS with ethanol to form fruity smell ester, this reaction is kown as esterification reaction. `underset("Acetic acid")(CH_(3)COOH)+underset("Ethanol")(C_(2)H_(5)OH)rarrunderset("Ethyl acetate")(CH_(3)COOC_(2)H_(5))+H_(2)O` (iii) Esterification process. |
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| 7756. |
An organic compound 'A' is a constituent of wine and beer and is also used as fuel in spirit lamp. Compound 'A' on heating with alkaline potassium permanganate gives another compound 'B' which turns blue litmus to red. Compound 'A' and 'B' combine in the presence of conc. H_(2)SO_(4) to give a sweet smelling compound 'C'. Identify compounds'A', 'B' and 'C'. Also write the equations involved in the reaction. |
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Answer» Solution :As compound .A. is a constituent of wine and BEER and is used in spirit lamp it is ethanol. `underset("A(Ethanol)") (CH_(3)CH_(2)OH) underset("Heat") overset("Alk. "KMnO_(4))to underset ("Turns BLUE litmus RED") underset("B(Ethanoic Acid)")(CH_(3)COOH)` `A+B overset("Conc. " H_(2)SO_(4))to C` `CH_(3)CH_(2)OH+CH_(3)COOHoverset("Conc. "H_(2)SO_(4))to underset("(Ester)") underset("Ethyl Ethanoate")(CH_(3)COOCH_(2)CH_(3)) +H_(2)O` |
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| 7757. |
An organic compound 'A' is a constituent of antifreeze and has the molecular formula C_(2)H_(6)O. Upon reaction with alkaline KMNO_(4), the compound 'A' is oxidised to another compound 'B' with formla C_(2)H_(6)O_(2). Identify the compounds 'A' and 'B'. Write the chemical equation for the reaction which leads to the formation of 'B'. |
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Answer» Solution :The compound 'B' should contain a `-COOH` group as it is an acid. Since it has only to carbon atoms, the other carbon ATOM must represent `CH_(3)` group. Thus, compound 'B' is ethanoic acid `(CH_(3)COOH)`. The compound 'A' used for the sterilisation of skin by DOCTORS is ethanol `C_(2)H_(5)OH (C_(2)H_(6)O)`. the chemical reaction involved in the oxidation by dilute alkaline `KMnO_(4)` solution also called Baeyer's reagent is: `underset("Ethanol (A)"(C_(2)H_(5)OH(l))+O_(2)(g)underset("reagent")overset("Baeyer's")tounderset("Ethanoic acid (B)")(CH_(3)COOH(l))+H_(2)O(l)` |
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| 7758. |
An organic acid 'X' is a liquid which often freezes during winter time in cold countries. It has molecular formula C_(2)H_(4)O_(2). On warming with ethanol in the presence of a few drops of conc. H_(2)SO_(4) a compound Y with a sweet smell is formed. (i) Identify 'X' and 'Y'. (ii) Write chemical equations for the reactions involved. |
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Answer» Solution :(a) .X. is `CH_(3)COOH and .Y. is CH_(3)COO CH_(2)CH_(3).` (b) `CH_(3)COOH + C_(2)H_(5)OHoverset(H_(2)SO_(4))rightarrowCH_(3)COOC_(2)H_(5)+H_(2)O` |
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| 7759. |
An organic acid X is a liquid , which of ten freezes during winter time in cold countries having the molecular formula C_(2)H_(4)O_(2). On warming it with methanol in the presence of a few drops of concentrated suphuric acid, a compound Y with a sweet smell is formed. (a) Identify X and Y .Also write the formula showing the functional group present in them. (b) Write a chemical equation for the reaction involved. |
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Answer» Solution :(i) X = Ethanoic acid `(CH_(3)COOH)` Y = Ethyl ethanoate `(CH_(3)COOC_(2)H_(5))` (ii) `underset("Ethanoic acid")(CH_(3)COOH)+underset("Ethanol")(C_(2)H_(5)OH) underset(Delta) overset("CONC. "H_(2)SO_(4))to underset("Ethyl ethanoate")(CH_(3)COOC_(2)H_(5))+H_(2)O` |
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| 7760. |
An ore when heated in air gives sulphur dioxide. Name the process that would be used for its concentration. |
| Answer» SOLUTION :FROTH FLOATATION | |
| 7761. |
An ore on treatment with dilute hydrochloric acid produces brisk effervescence. What type of ore is this ? What steps will be required to obtain metal from the enriched ore ? |
| Answer» Solution :Since the ORE gives brisk effervescence on reacting with dilute hydrochloric acid, it is likely to be a carbonate ore (sulphide ore can also be present). The METAL can be obtained by CARRYING out calcination, REDUCTION and refining. | |
| 7762. |
An ore on heating in air produces sulphur dioxide. Which process would you suggest for its concentration? Describe briefly any two steps involved in the conversion of this concentrated ore into related metal. |
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Answer» Solution :The ore on heating produces sulphur dioxide gas so it is a sulphide ore. The method used for its concentration is "froth floatation PROCESS" After concentration of the ore FOLLOWING two steps WOULD be followed to convert it into metal. (i) ROASTING: The sulphide ore is converted into its oxie by heating it in the PRESENCE of air `MS+O_2 to MO +SO_2 uparrow` |
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| 7763. |
An ore gives CO_2 on treatment with dilute acid. Identify the type of ore and name the process that should be used to convert this ore into oxide. |
| Answer» SOLUTION :CARBONATE ore, for example, CALCIUM carbonate. The ore is converted into oxide by calcination. | |
| 7764. |
An ore gives CO_2 on being treated with dilute hydrochloric acid. Which process should be used to convert this ore into oxide? |
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Answer» CALCINATION |
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| 7765. |
An ore contains arsenic and antimony as impurities. How are they removed during the process of roasting? |
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Answer» by CONVERSION into `As_(2)O_(3)andSb_(2)O_(3)` |
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| 7767. |
An odourless and colourless gas burns in air with a 'pop' sound. What the gas may be ? |
| Answer» SOLUTION :The GAS MAY be HYDROGEN. | |
| 7768. |
An odourless and colourless gas extinguishesa burning splinter of wood and turns limewater milky. What is the gas ? |
| Answer» SOLUTION :The GAS is CARBON DIOXIDE. | |
| 7769. |
An object is kept on the principal axis of a concave mirror of focal length 12 cm. If the object is at a distance of 18 cm from the mirror, calculate the image distance. Determine the nature of the image formed by calculating the magnification produced by the mirror. |
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Answer» Solution :Concave mirrorf = 12 cm focal length = 12 cm Object distance = 18 cm Nature of image = ? Formula : `(1)/(f) = (1)/(U) + (1)/(v)` `(1)/(v) = (1)/(f) - (1)/(u)` `(1)/(v) = (1)/(-12) - (1)/(18)` `(1)/(v) = -(1)/(12) + (1)/(18)` `(1)/(v) = - (1)/(36)` v = - 36 (real image in front of mirror ) magnification = - `(1)/(v)` = - `((-36))/(18)` = + 2 (upright ) Nature of iimage : Real and upright image OR Power = -0.5 D nagetive sign means : MYOPIA or short sightedness Power = `(1)/(f)` f = `(1)/(-0.5) = - (10)/(5) = -2.0 m xx 100` = - 200 cm Concave lens (diverging lens) In myopia, eye is unable to view long distance objects. The image in this case falls before the retina. For every myopic eye, there exists a far point beyond which clear image cannot be seen. The short-sightedness(myopia) is corrected by using a concave lens which diverges and shifts the image to the retina. 
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| 7770. |
An object 2cm tall is kept on the principal axis of a converging lens of focal length 8 cm. Find the position, nature and size of the image formed if the object is at 12cm from the lens. Also find the magnification produced by the lens. |
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Answer» Solution :Given: `h_0 = 2CM , f = 8cm ,u= -12cm , v ? ` ` 1/f = 1/v - 1/u` `1/v = 1/f + 1/u` `1/v = 1/8 - 1/12` `1/v = (3-2)/(24) = 1/24` REAL and INVERTED Real and inverted `(h_i)/(h_0) = v/u` ` (h_i)/((2) = (24)/(-12)` ` h_i= - 48/12 = -4` `h_o = - 4` MAGNIFICATION ` = v/u = (24)/(-12) = -2 ` |
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| 7771. |
An object is kept at the centre of curvature of a concave mirror. The position and nature of the image formed is |
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Answer» between F and C and inverted (D) at the centre of curvature and inverted . |
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| 7772. |
An LPG cylinder weighs 14.8 Kg when empty. When full, it weighs29.0 kg and shows a pressure of 2.5 atm. In the course of use at 27^(@)C, the weight of cylinder is reduced to 23.2 Kg. Find the volume of n-butane in cubic meters used up at 27^(@)C and 1 atm (Molecular weight ofn-butane = 58). |
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| 7773. |
An isotope of hydrogen without neutrons is ……………… . |
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Answer» DEUTERIUM `""_(1)H^(2)` |
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| 7774. |
An iron ring is to be coated with copper. How can we do this without using electricity ? |
| Answer» SOLUTION :Iron RING should be dipped in COPPER suphate solution. Iron displaces copper from sopper sulphate solution and copper is COATED on iron ring. | |
| 7775. |
An iron nail is dipped in CuSO_4, solution. (Reactivity order Fe>Cu) What is the change that can be noticed on the iron nail after a while? |
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| 7776. |
An iron nail is dipped in CuSO_4, solution. (Reactivity order Fe>Cu) Write down the CHEical equation of the oxidation reaction occurs here. |
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| 7777. |
An iron nail is dropped into a blue- coloured solution of copper sulphate. Will the colour of the solution turn red ? |
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| 7778. |
An iron knife kept dipped in a blue copper sulphate solution turns the blue solution to light green. |
| Answer» Solution :Iron is more reactive than copper. So, it DISPLACES copper from copper sulphate solution and forms FERROUS sulphate which is of LIGHT GREEN COLOUR. | |
| 7779. |
An ionic bond is formed when |
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Answer» the combining ATOMS GAIN electrons |
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| 7780. |
An increase in pressure increase the rate of reaction due to the increase in the number of collisions among the molecules . |
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| 7781. |
An increase in ............... increases the solubility of a gas in liquid. |
| Answer» SOLUTION :PRESSURE | |
| 7782. |
An external voltage opposing the cell potential is applied to a Daniel cell with zinc and copper electrodes. What happen when the external emf is increased from 0.8V to 1.1 Vand then 1.54 V ? |
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Answer» SOLUTION :(i) Working principle of Daniel CELL. (II) Calculation of cell emf. (iii) Comparison of the cell emf with the external VOLTAGE applied. (iv) DETERMINATION of direction of current depending on the magnitude of the external voltage |
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| 7783. |
An exothermic reaction is spontaneous at all temperature. What is the sign of S? |
| Answer» SOLUTION :`DELTA S = +ve` | |
| 7784. |
An example of triatomic molecule is ……….. . |
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Answer» OZONE |
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| 7785. |
An example of polyfunctional compound is |
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Answer» Glycine |
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| 7787. |
An exampleof hetro diatomicmoleculeisCO_(2) . |
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| 7789. |
An example of a liquid metal is___and that of a liquid non-metal is____ |
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Answer» GALLIUM, MERCURY |
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| 7790. |
An example of a complex salt is |
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Answer» ZINC sulphate |
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| 7791. |
An example for saturated hydrocarbon is |
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Answer» `C_2H_6` |
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| 7792. |
An example for saturated hydrocarbon is : |
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Answer» `C_(2) H_(6)` (A) `C_(2)H_(6)` |
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| 7793. |
An example for detergent is |
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Answer» SODIUM lauryl SULPHATE |
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| 7794. |
An ester has the molecular formula C_(4)H_(8)O_(2). Write its structural formula. What happens when this ester is heated in the presence of sodium hydroxide solution? Write the balanced chemical equation for the reaction and name the products. What is a saponification reaction? |
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Answer» Solution :Structural formula: `H-underset(H)underset(|)overset(H)overset(|)C-overset(O)overset(||)C-O-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H` When this ester is heated in the presence of SODIUM hydroxide solution, it changes into an alcohol and a carboxylic acid. `CH_(3)COOC_(2)H_(5) overset("NaOH")to CH_(3)COOH+C_(2)H_(5)OH` Products: Ethanol and ethanoic acid Saponification: REACTION of an ester with an acid or a base to GIVE an alcohol and a carboxylic acid. This reaction is known as SPONIFICATION because it is used in the PREPARATION of soap. |
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| 7795. |
An empty evaporating dish weighs 20.0 g. After adding saturated solution of NaNO_3, the dish weighs 66.0 g. When evaporated to dryness, the dish with crystals weighs 41.5 g. Find the solubility of NaNO_3, at 20^@ C. |
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Answer» SOLUTION :WEIGHT of SATURATED solution of `NaNO_3 = (66.0 – 20.0) g = 46.0 g` Weight of crystals of` NaNO_3` = (41.5 – 20.0) g = 21.5 g Weight of water in saturated solution = (46.0 – 21.5) g = 24.5 g Solubility of `NaNO_3= ("weightof" NaNO_3"Crystals")/("weight ofwater ") xx 100` `=(21.5 )/( 24.5 ) xx 100 =87.7 g ` Solubility of `NaNO_3` at `20^@ ` Cis = 87.7 in100 g `H_2 O` |
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| 7796. |
An element Z has atomic number 16. Answerthe following questions on Z: State the period and group to which zbelongs. |
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| 7797. |
An element Z has atomic number 16. Answerthe following questions on Z: What kind of a compound is this? |
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| 7798. |
An element Z has atomic number 16. Answerthe following questions on Z: State the formula between Z and Hydrogen. |
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| 7799. |
An element Y has three shells with four electrons in the valence shell. Another element X has twice as many electrons in its second shell as in its first shell. i] Identify the elements X and Y. ii] Is there any similarity between the element Y and X? If so, what? |
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Answer» Solution :i] Electronic CONFIGURATIONS are: X = (2, 4) and Y = (2, 8, 4) and hence atomic numbers are 6 and 14 respectively. Hence, X is identified as carbon and Y as silicon. ii] YES, there is a similarity between X and Y. Both have 4 VALENCE electrons and hence have the same CHEMICAL properties and belong to the same group. |
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| 7800. |
An element Z has atomic number 16. Answerthe following questions on Z: Is Z a metal or a non-metal ? |
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