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InterviewSolution
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.
| 1351. |
What is called rancidity ? What is the general name of chemicals which are added to fat and oil containing food to prevent the rancidity ? |
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Answer» Solution :When oil and fat containing FOOD is exposed to air, it reacts with oxygen and gets oxidised. As a RESULT, food become rancid and their TASTE and smell changes. This PROCESS is called rancidity. The general name of the chemicals which are added to food to prevent its rancidity are known as ANTIOXIDANTS. For example, Nitrogen gas is an antioxidant substance. |
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| 1352. |
Which amongst the following will not conduct electricity? |
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Answer» NaCl |
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| 1353. |
What is meant by percentage composition ? What is its use ? |
| Answer» Solution :The percentage COMPOSITION of a COMPOUND represents the mass of each element PRESENT in 100 g of the compound. It is useful to determine the empirical formula and molecular formula. | |
| 1354. |
Why can we not use an aqueous solution of sodium chloride to isolate sodium metal by electrolysis ? |
| Answer» Solution :Because in aqueous solution of active metalthe `H^(+)` ION of WATER is REDUCED in preference to `Na^(+)` ion. | |
| 1355. |
Write the chemical equation for the following : Methane on burning combines with oxygen to form carbon dioxide and water. What is the need of balancing the equation ? |
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Answer» Solution :`CH_(4)+2O_(2)toCO_(2)+2H_(2)O` The need of balancing the equation is that an equation should be written as PER the law of conservation of mass. It states that the number of atoms of each ELEMENT before and after the REACTION should remain same. |
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| 1356. |
Which of the following is used for dissolution of gold ? |
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Answer» a)HYDROCHLORIC ACID |
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| 1357. |
Write the names of functional groups in : (i) CH_(3)-overset(O)overset(||)C-CH_(3)(ii) CH_(3)-CH_(2)-overset(O)overset(||)C-OH |
| Answer» SOLUTION :Ketonic GROUP (II) CARBOXYLIC group | |
| 1358. |
What is homo atomic molecule ? Give two examples. |
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Answer» Solution :If the MOLECULE is made of similar KIND of ATOMS, then it is called homoatomic molecule. e.g. `H_(2), Cl_(2)` |
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| 1359. |
Which one of the following will have largest number of atoms ? (a) 1g Au (s)(b) 1g Na (s)(c) 1g Li (s)(d) 1g of Cl_(2)(g) |
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Answer» |
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| 1360. |
What is the difference between two consecutive members in a homologous series in alkanes in terms of : (i) Molecular mass (ii) Number of atoms of elements. |
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Answer» Solution :Difference in N. (i) MOLECULAR MASS = 14 a.m.u. (II) Number of atoms of elements = `CH_(2)`. |
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| 1361. |
X is formed by the partial replacement of hydroxyl groups of a diacidicbase by an acidic radical. The number of ionizable hydroxyl groups in X is ______ |
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Answer» 0 |
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| 1362. |
Using the part of the Periodic Table given below, answer the questions that follow : (i) Na has physical and chemical properties similar to which element(s) and why? (ii) Write the electronic configuration of N and P. Which one of these will be more electronegative and why? (iii) State a chemical property common to fluorine and chlorine. |
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Answer» Solution :(i) Physical and CHEMICAL properties of Na are similar to those of elements Li and K because they belong to the same group (Group I). (ii) Electronic configuration N : 2, 5 P : 2, 8, 5 Nitrogen atom being SMALLER in size than phosphorus, can hold the electrons more tightly than phosphorus. Electronegativity (or non-metallic character) decreases down the group. THEREFORE, N is more electronegative than P. (iii) Fluorine and chlorine both have ONE electron in the valence shell. Both of them have the valency 1. |
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| 1363. |
What is decarboxylation reaction? |
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Answer» Solution :When a sodium salt of ethanoic acid is HEATED with soda lime (solid mixture of 3 parts of NaOH and 1 part of CaO), methane GAS is formed. During this reaction `CO_(2)` molecule is eliminated. Therefore, this reaction is called decarboxylation reaction. `underset(("Sodium acetate"))(CH_(3)COONa)underset(Delta)overset(NaOH//CaO)rarrunderset(("Methane"))(CH_(4)uarr)+Na_(2)CO_(3)` |
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| 1364. |
What are the carboxylic acids called in the IUPAC system of nomenclature ? |
| Answer» SOLUTION :Alkanoic ACID . | |
| 1365. |
The temperature applied in Hall's processis ………… and the voltage used in ……………. |
| Answer» SOLUTION : 900 - `950^(@)`C, 5-6V | |
| 1366. |
What is neutralisation reaction? |
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Answer» Solution :A DOUBLE DISPLACEMENT REACTION occurring between an acid and a base GIVING only salt and water as products is called neutralization reaction. Its general form is : Acid `+` Base `to` Salt `+` water |
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| 1367. |
Why are ionic compounds solid and hard at room temperature? |
| Answer» SOLUTION :In an ionic COMPOUND, the charged IONS are TOGETHER by strong electrostatic forces of ATTRACTION. | |
| 1368. |
Which gas is produced when dilute hydrochloric acid is added to a reactive metal ? Write the chemical reaction when iron reacts with dilute sulphuric acid H_2SO_4 |
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Answer» Solution :Hydrogen GAS is produced when dilute HYDROCHLORIC ACID is added to a reactive METAL. Metal + Dil. Hydrochloric acid `to`Metal chloride + Hydrogen `Fe(s) + H_2SO_4(aq) overset(dil)(to) FeSO_4 (aq) + H_2(g)` |
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| 1369. |
Why are more electropositive elements extracted only by electrolytic reduction? |
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Answer» Solution :(i) Electrode POTENTIALS of highly electropossitive elements. (II) The FORM (ore) in which the metals are available in nature. (iii) Relation between elecropositivity of the metal and the chemical stability of the respective ore. (iv) Relation between the ELECTROPOSITIVITY of the metal and the tendency of it to get reduced. (v) MECHANISM of electrolytic reduction. |
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| 1370. |
The structural formula of an ester is CH_3CH_2COOC_2H_5. Write the formula of the acid and alcohol from which this ester is formed. |
| Answer» SOLUTION :ACID ` = CH_3CH_2COOH` , ALCOHOL ` = C_2H_5OH` | |
| 1371. |
What were the criteria used by Mendeleev in creating his periodic table ? |
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Answer» Solution :The following CRITERIA was used by Mendeleev in creating his periodic table : (1) The properties of elements are the periodic function of their ATOMIC masses. (2) Elements with similar properties are arranged in the same group. ( 3 ) The formula of oxides and HYDRIDES formed by an ELEMENT. |
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| 1372. |
Which of the following statements are correct about a chemical aquilibrium? (i)It is dynamic in nature (ii)The rate of the forward and backward reactions are equal at equilibrium (iii)Irreversible reactions do not attain chemical equilibrium (iv)The concentration of reactants and products may be different |
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Answer» I,ii and iii Rate of forward reaction=Rat of backward reaction |
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| 1374. |
What is meant by unbalanced chemical equation ? |
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Answer» SOLUTION :Chemical EQUATION is written more concisely by using chemical formulae instead of words, then such equation is called unbalanced equation. For EXAMPLE, `Mg + O_(2)to MgO` In the above equation, mass and NUMBER of atoms are not same on both side. Hence, this is an unbalanced chemical equation. It is also called SKELETAL chemical equation for the burning of magnesium in air. |
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| 1375. |
Which of the following may be regarded as weak electrolytes? |
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Answer» NACL |
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| 1376. |
When two moles of hydrogen are heated with two moels of iodine, 2.96 moles of hydrogen iodide are formed. Calculate K_(c) for the reaction of formation of hydrogen iodide. |
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Answer» Solution :`H_(2)(G)+I_(2)(g) HARR 2HI(g)` At equilibrium, `2-X""2-x""2X` `2x=2.96` `x=(2.96)/(2)=1.48` `K_(c)=([HI]^(2))/([H_(2)][I_(2)])=((2x)^(2))/((2-1.48)(2-1.48))=(4XX(1.48)^(2))/(0.52xx0.52)=32.4` |
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| 1377. |
Write the name and general formula of a chain of hydrocarbons in which ar addition reaction with hydrogen can take place Stating the essential conditions required for an addition reaction to occur, write the chemical equation giving the name of the reactant and the product of such a reaction. |
Answer» Solution :Name and general FORMULA of hydrocarbons undergoing addition reaction with hydrogen : Essential conditions required for the addition reaction to occur : (i) Multiple bonds (double and TRIPLE bonds) must be present between carbon atoms in the CHAIN of hydrocarbon. (ii) Addition of hydrogen should be carried out in the presence of catalyst such as nickel or platinum. Chemical EQUATION: `underset("Ethene")(CH_(2))=CH_(2)+H_(2)overset"(Ni ot Pt)"rightarrow underset("Ethene")(CH_(3) - CH_(3))` `underset("Ethene")(CH-)= CH+2H_(2)overset"(Ni ot Pt)"rightarrow underset("Ethene")(CH_(2))= CH_(2)` |
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| 1378. |
valency of an element is determined by the number of electrons present in the first shell. Giving reasons, explain the following : (a) Element A is a non-metal. (b) Element B has a larger atomic size than element C. (c) Element Chas a valency of 1. |
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Answer» Solution :(a) Element A (Group VII or 17) is a non-metal because it has 7 valence electrons. It has a tendency to gain one electron to complete the OCTET. ELEMENTS which have a tendency to gain electrons are non-metals. (b) As we move from left to right in a period, the effective nuclear charge INCREASES. The nucleus attracts the outermost electrons in the valence shell with greater force. This decreases the size of the ATOM as we move from left to right. That is why B has a larger ATOMIC size than element C. (c) Chas seven electrons in the outermost shell. In order to complete its octet, it gains one electron. Hence, its valency is one. |
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| 1379. |
What is the molecular formula of the alcohol which can be derived from propane? |
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Answer» SOLUTION :PROPANE: `CH_(3)-CH_(2)-CH_(3) or C_(3)H_(8)` ALCOHOL obtained from propane is `C_(3)H_(7)OH`. |
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| 1380. |
Theweightof a molecule of the compoundC_(60 ) H_(122)is : |
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Answer» `1.4xx 10 ^(-21)g` `=("Moleculesmass " xx"No… OFPARTICLES ")/( "Avagardro's No .")` `= 842xx 6.023xx 10 ^(23)` `=139.797xx 10^(-23) = 1.39797 xx 10 ^(-21)` g ` C_(60 )H_(122) = 12xx60+1xx122` `= 720 +122= 842` |
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| 1381. |
Which order of relative size amongst the following is incorrect ? |
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Answer» `LI lt Na lt K` |
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| 1382. |
Write the structural formula of three isomers of pentane C_(5)H_(12). |
Answer» SOLUTION :
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| 1383. |
Water contains hydrogen and oxygen in the ratio of 2:1. Prove it by an activity. |
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Answer» Solution :Take a plastic mug. Drill two holes at its base and fit rubber stoppers into these holes. Insert carbon electrodes in these rubber stoppers as shown in the figure. CONNECT electrodes to a 6 volt battery. FILL the mug with water such that the electrodes are immersed and add a few drops of DILUTE sulphuric acid to the water to make it conducting. Take two test tubes filled with water and invert them over the two carbon electrodes. Switch on the current and leave the apparatus undisturbed for sometime.  You will observe the formation of bubbles at both the electrodes. These bubbles displace water of the test tubes. The gas collected in test tube attached to cathode is TWICE in volume than the gas collected at anode. Once the test tubes are filled with the gases, remove them carefully. The gases can be tested by bringing a BURNING candle close to the mouth of each test tube. A gas at anode make the candle to light brightly indicating it is oxygen while a gas at cathode burns with popping sound indicating it is hydrogen. |
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| 1384. |
Write the number of covalent bonds in the molecules of butane C_(4)H_(10). |
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Answer» |
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| 1385. |
Which of the metals displaces hydrogen gas from hydrochloric acid?Silver or zinc.Give the chemical equation of the reaction and justify your answer. |
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Answer» Solution :Zinc displaces HYDROGEN GAS from hydrochloric ACID. Zinc is more reactive than SILVER `Zn+2HCltoZnCl_(2)+H_(2auarr` |
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| 1386. |
While cooking if the bottom of the vessel is getting blackened on the outside, it means that : |
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Answer» the FOOD is not COOKED completely |
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| 1387. |
What happens when metals react with water ? Give one example. |
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Answer» SOLUTION :INERT and very less reactive METALS do not REACT with cold or hot water. Less reactive metals do not react with cold water but reacts with hot water. `Fe+H_(2)Ooverset("Very high TEMP.")toFe_(2)O_(3)+H_(2)-` Very reactive metals react with cold water to produce hydrogen as. `Na+H_(2)OtoNaOH+H_(2)uarr` |
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| 1388. |
Which of the following has highest concentration of hydrogen ion? |
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Answer» SOLUTIONI with PH=4 pH and `H^(+)` ION concentration are inversely RELATED. pH and acidic strengths are ALSO inversely related. |
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| 1391. |
Which among the following are unsaturated hydrocarbons ? (i) H_(3)C-CH_(2)-CH_(2)-CH_(3) (ii) H_(3)C-C-=C-CH_(3) (iii) H_(3)C-underset(CH_(3))underset(|)(CH)-CH_(3) (iv) H_(3)C-underset(CH_(3))underset(|)(C)=CH_(2) |
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Answer» (i) and (III) |
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| 1392. |
What is the solubility of product in water obtained by the reaction of Cu, Fe, Zn, Al with oxygen ? |
| Answer» Solution : The products obtained by the reaction of Cu, Fe, ZN and Al with OXYGEN are INSOLUBLE in WATER. | |
| 1393. |
Which of the following is an organic acid? |
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Answer» SULPHUROUS ACID |
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| 1394. |
Write the name of the compound having the following formula:CH_3-oversert(CH_3) overset(|) CH-CH_3 underset(1)CH_3 - underset(2)overset(CH_3)overset(|)(CH) - underset(3)(C )H_3 |
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Answer» Solution :IUPAC parts of the complete name of the structural formula: Root word, Primary SUFFIX, SECONDARY suffix, Prefix.(i) (a) There are 3 C ATOMS in the CONTINUOUS chain. Therefore, root word = prop. (b) Only C-C covalent bonds are present in the chain. Therefore, primary suffix is ane. (c) There is no functional group with the parent chain. Therefore, secondary suffix is not involved. (d) There is a SUBSTITUENT of methyl radical `(-CH_3)`on carbon 2. Therefore, prefix is 2-methyl. Thus the IUPAC name of the given compound is derived as: Prefix + Root word + Primary suffix 2-Methyl + prop + ane = 2-Methylpropane |
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| 1395. |
Which of the following is used for making magnets ? |
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Answer» DURALUMIN |
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| 1396. |
When the powder of a common metal is heated in an open china dish, colour turns black. However, when hydrogen gas is passed over the hot black substance formed, it regains its original colour. Based on this information, answer the following questions : (i) What type of chemical reaction takes place in each of the two given steps ? (ii) Name the metal initially taken in the powder form. Write balanced chemical equations for both these reactions. |
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Answer» Solution :(i) The available information suggests the metal is copper. In open AIR, its is oxidised to form copper (II) oxide which is black in colour. The REACTION is known as oxidation reaction. On passing hydrogen gas over the hot substance, the original colour of the metal is regained. It is an example of reduction reaction. (ii) The balanced chemical equations for the reactions are : `underset(("Metal"))(2Cu(s)) + O_(2)(g) overset("HEAT")rarr underset(("Black"))underset("Copper (II) oxide")(2CuO(s))` `CuO(s) + H_(2)(g) overset("heat")rarrCu(s) + H_(2)O(g)` |
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| 1398. |
when excess of a base is dissolved in a solution of sodim hydroxide, the concetration of hydroxide ion in the solution decrease. |
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Answer» |
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| 1400. |
Zeeman and Stark effects can be explained by _ quantam number |
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Answer» PRINCIPAL |
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