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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.
| 351. |
Though oxygen and sulphur belong to the same ltbegt group, sulphur shows many oxidationn states, whereas oxygen does not show a higher oxidation state than that of -2. Comment. |
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Answer» Solution :(i) COMPARISON of electronic configuration of oxygen and sulphur (ii) presence of vacant 'd' SUBSHELL and SCOPE for excited state configuration |
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| 352. |
The type of medicine used to treat indigestion is |
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Answer» antihistamic |
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| 353. |
Two elements X and Y belong to group 1 and 2 respectively in the same period of the periodic table. Compare these elements with respect to : (i) number of electrons in their outermost orbit (ii) their valencies (iii) metallic character (iv) their atomic size (v) formula of their chlorides (vii) formula of their sulphates. |
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Answer» Solution :(i) Number of electrons in the outermost ORBIT of X = 1 and Y = 2. (II) Valency of X = 1 and Y =2. (III) Metal X is more metallic than Y. (iv) Atomic size of X is bigger than that of Y. (v) Chloride `XCl,YCl_(2)` (vi) SULPHATE `X_(2)SO_(4),YSO_(4)` |
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| 354. |
Zinc is refined by |
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Answer» Iiquation (or) DISTILLATION under REDUCED PRESSURE |
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| 355. |
Which of the following properties generally decreases along a period? |
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Answer» ionisaiton energy |
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| 356. |
Which of the following acid is used by goldsmiths for cleaning gold and silver ornaments? |
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Answer» HCI |
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| 357. |
Three elements 'X', 'Y' and 'Z' have atomic numbers 7, 8 and 9 respectively. (i) State their positions (Group number and period number both) in the Modern Periodic Table. (ii) Arrange these elements in the decreasing order of their atomic radii. (iii) Write the formula of the compound formed when 'X' combines with 'Z'. |
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Answer» Solution :(i) X (7) = 2,5 GROUP 15, Period 2 Y(8) = 2,6 Group 16, Period 2 Z(9) = 2,7 Group 17, Period 2 (ii) `XgtYgtZ` (iii) `XZ_(3)` |
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| 358. |
What is ionisation energy? How does ionisation energy vary along the period in the modern periodic table ? |
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Answer» Solution :The energy required to remove the electron from the outermost SHELL of an isolated gaseous atom is KNOWN as ionisation energy. It INCREASES while going from left to RIGHT in modern periodic table. |
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| 359. |
What colour changes do you observe when : (i) you add Zn to a solution of copper sulphate ? (ii) you add Pb to a solution of cupric chloride ? Write balanced equations. |
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Answer» Solution :(i) BLUE colour of COPPER sulphate disappears. `ZN(s)+CuSO_(4)(aq) to ZnSO_(4)(aq)+Cu(s)` (ii) Green colour of cupric chloride disappears. `Pb(s)+CuCl_(2)(aq)toPbSl_(2)(aq)+Cu(s)` |
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| 360. |
What happends when zinc pieces are added to aqueous copper sulphate solution and copper pieces are added to aqueous zinc sulphate solution ? Justify |
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Answer» Solution :(i) Electrochemical SERIES (II) Comparison of standard electrode potentials of zinc and copper. (iii) Comparison of REACTIVATES of zinc and copper with respect of their dipositive ions. (IV) OBSERVABLE change in the solution corresponding to the reation involved |
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| 361. |
Write the electron-dot structures for sodium, oxygen and magnesium. |
Answer» SOLUTION :
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| 362. |
Tooth enamel is made up of: |
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Answer» MAGNESIUM HYDROXIDE |
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| 363. |
Which of the following metals exist in free state in nature ? |
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Answer» Mg |
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| 364. |
The tetravalency of carbon is explained by its |
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Answer» ground STATE electronic configuration |
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| 365. |
Write the balanced chemical equation of the reaction between sodium carbonate and dilute hydrochloric acid . |
| Answer» SOLUTION :`Na_(2)CO_(3) +2HCI to 2NaCI +H_(2)O +CO_(2)` | |
| 366. |
Write the formula of the following groups : (a)aldehyde (b)ketone |
Answer» SOLUTION :
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| 367. |
The removal of hydrogen from a substance in a chemical reaction is known as |
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Answer» Reduction |
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| 368. |
Using the part of the periodic table given below, answer the questions that follow. (i) Na has physical properties similar to which elements and why ? (ii) Write the electronic configuration of N and P. (iii) State one property common to fluorine and chlorine. |
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Answer» Solution :(i) Na has physical properties similar to Li and K. All the three elements have one electron each in the VALENCE shell of their atoms. These are known as alkali metals. However, the element hydrogen has different physical properties since it is not a part of the group of alkali metals. (ii) Electronic CONFIGURATION of N (Z = 7) = 2, 5 Electronic configuration of P (Z = 15) = 2, 8, 5 (iii) Both the elements have seven electrons in the valence SHELLS as their atoms and have VALENCY equal to one. Fluorine (Z = 9) 2, 7 , Chlorine (Z = 17) 2, 8, 7. |
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| 369. |
The solution of a salt is basic. The salt must be |
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Answer» `KNO_3` |
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| 370. |
What asre amphoteric oxides? Choose the amphoteric oxide from among the followng oxides: Na_(2)O,ZnO,Al_(2)O_(3),CO_(2),H_(2)O |
| Answer» Solution :Those OXIDES which reacts with acidse as well bases to produce salts and water CALLED amphoteric oxide. Among GIVEN oxides `ZnO, Al_(2)O_(3)` are amphoteric. | |
| 371. |
Write the formation of magnesium chloride. |
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Answer» Solution :FORMATION of magnesium chloride `(MgCl_2)`: The atomic number of magnesium is 12. It has two electrons in its valence shell as shown below: `_12Mg-2,8,2` Magnesium therefore has a tendency to lose the 2 valence electrons and in the process attains the electronic configuration of neon. `Mg_(2,8,2)toMg_(2,8)^(2+)+2E^-` Chlorine(atomic number 17) has 7 electrons in the valence shell. It has a tendency to gain one electron to complete its octet. `Cl_(2,8,7)+e^(-) toCl_(2,8,8)^(-)` Thus , when magnesium and chlorine are BROUGHT together, the magnesium atom transfers its two valence electrons to two chlorine atoms. In the process, both the atoms acquire the stable electronic configuration of nearest inert gases. The positively charged magnesium ion `Mg^(2+)` and negatively charged chloride ions `(Cl^-)` are now held together by the electrostatic force of attraction and form ionic bond. `Mg^(2+)+2Cl^(-) to Mg^(2+) 2Cl^(-)or MgCl_2` this process can also be shown as below: 
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| 372. |
Which one of the following will not decolourize bromine solution? |
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Answer» `C_2H_6` |
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| 373. |
What do you think? Should hydrogen be placed in the group 17 of halogens or group 1 of alkali metals in the Modern Periodic table? |
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Answer» Solution :(i)Hydrogen fits in its current position in theperiodic table (group 1) much better than ingroup 17 (THOUGH is not a perfect position). FOREXAMPLE Hydrogen forms oxide (`H_2O`) just likeoxides of alkali METALS `(Na_2O,K_2O)`. It has the same common charge ( + 1) as all alkali metals. (ii) It resembles halogens in forming diatomicmolecules `H_2,Cl_2,F_2,Br_2`. (iii) It does not behave like halogens, being mainly in the + 1 oxidation state. It does not happen to be like halogens, the most STABLE compounds of halogens have either -1 or a very high oxidation state like -7 or +5.) (iv) Hydrogen has one electron in the outermost shell and it is placed in top of group/based on atomic number. |
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| 374. |
Which of the following indicates that the bonding in hydrogen chloride is covalent ? (i) an aqueous solution of hydrogen chloride form hydrogen with metals (ii) hydrogen chloride is a gas (iii) hydrogenchloride is not acidic in the absence of water (iv) dry hydrogen chloride is a non-conductorof electricity |
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Answer» (II), (III) and (IV) only |
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| 375. |
Two solutions A and B have pH values of 5 and 8 respectively . Which solution will be basic in nature ? |
| Answer» SOLUTION :Solution B. | |
| 376. |
Which of the following is an alkali ? |
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Answer» FERROUS HYDROXIDE |
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| 377. |
What happens when calcium is treated with water? (i) It does not react with water. (ii) It reacts violently with water. (iii) It reacts less violently with water. (iv) Bubbles of hydrogen gas formed stick to the surface of calcium. |
| Answer» SOLUTION :Calcium reacts LESS violently with water and BUBBLES of hydrogen gas stick to its surface. | |
| 378. |
What is Debereiner's law of triads? Explain with the help of one example of a Dobereiner's triad. |
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Answer» |
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| 379. |
Which one will not displace copper from copper sulphate? |
| Answer» SOLUTION :Silver | |
| 380. |
Which of the following gas is known as illumi nating gas? |
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Answer» Ethane |
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| 381. |
Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason. |
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Answer» Solution :Noble gases. According to the Mendeleev.s classification, the properties of elements are the periodic function of their atomic masses and there is a periodic RECURRENCE of elements with similar physical and CHEMICAL properties. Noble gases being INERT, could be placed in a separate group without disturbing the ORIGINAL order. |
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| 382. |
What do you understand by the term periodicity? Does the periodicity in properties is a functionof valence electrons? Illustrate. |
| Answer» Solution : When the elements are arranged in ORDER of INCREASING atomic numbers, elements with similarchemical properties are repeated at definite intervals. This is known as periodicity. Yes, this periodicity is due to the periodicity in the number of ELECTRONS in the outermost shell of the atoms of the elements. If elements having the same number of valence electrons are GROUPED together, theelements falling within each group are similar in CHEMICAL properties. | |
| 383. |
Volume occupied by 16 g of oxygen is same as that occupied by 1 of hydrogen under similar conditions of temperature and pressure. Explain. |
| Answer» Solution :Both 16 G of OXYGEN and 1 g of HYDROGEN corresponds to ` 0.5` moles of molecules and hence, occupy same volume under similar conditins of TEMPERATURE and pressure. | |
| 384. |
What would be the electron dot structure of a molecule of sulphur which is made-up of eight atoms of sulphur ? [Hint : The eight atoms of sulphur are joined together in the form of ring.] |
Answer» SOLUTION :The ELECTRONIC CONFIGURATION of `""_(16)S` is as FOLLOWS : 
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| 385. |
Which one of the following ios not an ores ofalumimium ? |
| Answer» Answer :B | |
| 386. |
What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur ? |
Answer» SOLUTION :The eight ATOMS of sulphur are joined TOGETHER in the FORM of ring. 
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| 387. |
Which of the following element will gain an electron easily? |
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Answer» Mg |
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| 388. |
What are isotopes ? Give example. |
| Answer» Solution :Atoms of the same element that have same atomic NUMBER but DIFFERENT mass number are CALLED isotopes. e.g., `""_(1)H^(1),""_(1)H^(2),""_(1)H^(2)` | |
| 389. |
Where would you locate the element with electronic configuration 2, 8 in the Modem Periodic Table ? |
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Answer» Group 8 |
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| 390. |
What is the difference between the molecules of elements and compounds? |
| Answer» Solution :Molecules of elements contain atoms of the same element where as molecules of COMPOUNDS contain atoms of TWO or more DIFFERENT elements. | |
| 391. |
You have two solutions A and B. The pH of the solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration ? Which of these acidic and which one is basic ? |
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Answer» Solution :The pH of a solution is inversely PROPORTIONAL to its hydrogen ION concentration. This means that the solution having lower pH will have more hydrogen ion concentration. Thus, solution A will have more hydrogen ion concentration . A solution with `pH LT 7` is acidic. Hence , solution A is acidic. A solution with `pH gt 7` is BASIC . Hence , solution B is basic . |
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| 392. |
To which group do the elements belong? What is the family called? |
| Answer» Solution :The ELEMENTS BELONG to group 1. The FAMILY is called as ALKALI metals. | |
| 393. |
Which of the following reactions is called roasting? |
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Answer» `ZnCO_3(s ) overset(Delta )(to) ZNO(s) + CO_2(g)` |
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| 394. |
Write the chemical equations for the conversion of ethanol to ethanoic acid in the presence of KMnO_(4). |
| Answer» Solution :`UNDERSET"Ethanol"(CH_(3)CH_(2))OHoverset(KMnO_(4))rightarrowunderset"ETHANOIC acid"(CH_(3)COOH)` | |
| 395. |
Write the balanced chemical equation for the following and identify the type of chemical reaction in each case. hydrogen (g) + chlorine (g) to Hydrochloric acid (g) |
| Answer» SOLUTION :`H_(2)(G)+Cl_(2)(g)to2HCl(g)-` combination reaction. | |
| 396. |
Write the balanced chemical equation for the following and identify the type of chemical reaction in each case. potassium bromide (aq.) + Barium iodide (aq.) to potassium iodide (aq.) and barium bromide (aq.) |
| Answer» SOLUTION :`2KBr(aq.)+Bal_(2)(aq.)to2Kl(aq.)+BaBr_(2)(aq.)-` DOUBLE - DISPLACEMENT reaction. | |
| 397. |
What does (II) indicate in iron (II) oxide ? |
| Answer» SOLUTION :VALENCY of FE (OXIDATION NUMBER) | |
| 398. |
Which colour change and smell are observed when crystals of ferrous sulphate are heated ? Give chemical reaction also. |
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Answer» Solution :Green colour of ferrous sulphate disappears and a SMELL of burning sulphur is noticed. `underset("(Green)")underset("Ferrous sulphate")(2FeSO_(4).7H_(2)O)OVERSET(Delta)(to)underset("OXIDE")underset("Ferric")(Fe_(2)O_(3))+underset("smell")underset("sulphur")underset("Burning")(SO_(2)+SO_(3))+14H_(2)O` |
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| 399. |
When Sodium sulphate reacts with barium chloride a white precipitate of _____ is formed? |
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Answer» `Na_2SO_4` |
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| 400. |
Which of the following is false for paramagnetic species |
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Answer» They have temporary dipoles |
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