InterviewSolution
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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.
| 551. |
Which one of the following depict the correct representation of atomic radius (r) of an atom ? |
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Answer» (i) and (II) |
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| 552. |
When red litmus is added to a solution of borax, it turns blue. What can you say about the pH of borax solution? |
| Answer» SOLUTION :BASIC solution and `pHgt7` | |
| 553. |
What is malleability of metals ? |
| Answer» Solution :The property of metals to be CONVERTED into THIN SHEETS when HAMMERED is known as .Malleability of metals.. | |
| 554. |
The resistivity of manganese wire of length 1 m is 1.84 xx 10^(-6) Omega m at 20^(@) C. If the diameter of the wire is 3 xx 10^(-4) m, what will be the resistance of the wire at that temperature ? OR Observe the given circuit : Calculate the total resistance in the circuit and the total current flowing in the circuit. |
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Answer» Solution :Resistivity `rho= 1.84 xx 10^(-6) Omega` m Length l = 1m DIAMETER d = `3 xx 10^(-4)` m Area of cross- section A = `(pi d^(2))/(2)` ` = (22)/(7) xx (3 xx 10^(-4) xx 3 xx 10^(-4))/(4)` = `(99)/(14) xx 10^(-8) m^(2)`. Resistance R = `(rho xx l)/(A)` = `(1.84 xx 1 xx 14 xx 10^(-6))/(99 xx 10^(-8))` ` = (22.76 xx 10^(2))/(99)` = `26.02 Omega` OR - In parallel connection, ` (1)/(R_(p)) = (1)/(R_(1)) + (1)/(R_(2)) + (1)/(R_(3)) rArr (1)/(R_(p)) = (1)/(2) + (1)/(4) + (1)/(4) ` ` rArrR_(p) = 1 Omega` . Total resistance in the CIRCUIT R = `R_(p) + R_(4)` = 1 + 5 ` = 6 Omega` `therefore" Current " I = (V)/(R) = ( 6)/(6) = 1` A . |
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| 555. |
Write the balanced chemical equation and identify the type of reaction : Hydrogen(g) + Chlorine(g) to Hydrogen chloride(g) |
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Answer» Solution :`H_(2)(G)+Cl_(2)(g) to 2HCl(g)` GIVEN REACTION is a combination reaction. |
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| 556. |
Whichof thefollowinghas largestnumberof particels ? |
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Answer» `8 g" of " CH_4` |
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| 557. |
What is atomic radius? Why does atomic radius decrease across a period? |
| Answer» Solution :Atomic radius is defined as the distance from the centre of the nucleus of an atom to the outermost shell of electrons. The atomic radius decreases along a PERIOD. In moving from left to right across the period, the charge on the nucleus increases by ONE UNIT (DUE to increase in atomic number), but the additional electron goes to the same shell. As a result, outer electrons are pulled in CLOSER to thenucleus. This causes the decrease of atomic size. | |
| 558. |
HARD AND SOFT WATER |
| Answer» Solution :Hard water CONTAINS the bicarbonates, chlorides or sulphates of CALCIUM and MAGNESIUM , whereas soft water is FREE from these substances. | |
| 559. |
Three acidic solutions A, B and C have pH = 0, 3 and 5 respectively. (i)Which solution has highest concentration of H^+ ions ? (ii) Which solution has the lowest concentration of H^+ ions ? |
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Answer» Solution : SMALLER the pH value, higher the concentration of `H^+` IONS. (i) Solution A has the highest concentration of `H^+` ions. (ii) Solution C has the lowest concentration of `H^+` ions |
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| 560. |
Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table? |
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Answer» GROUP 8 |
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| 561. |
Which of the following substances will not give carbon dioxide on treatment with dilute acid? |
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Answer» Marble |
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| 562. |
Write molecular, electronic and structural formulae of ethene. |
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Answer» SOLUTION :Molecular formula:`C_(2)H_(4)` Electronic formula:  Structural formula:`H-UNDERSET(H)underset(|)C=underset(H)underset(|)C-H` |
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| 563. |
Which of the following sequence of metals is in the order of their increasing electrical conductivity ? |
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Answer» CU ` lt Au lt Ag lt AL` |
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| 564. |
Which one of the following will have largest number of atoms? (i) 1gAu(s) (ii) 1gNa(s) (iii) 1gLi(s) (iv) 1g" of "Cl_(2)(g) ("Atomic masses : Au = 197, Na = 23, Li = 7, Cl = 35.5 amu") |
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Answer» SOLUTION :(i)`"1 g Au"=(1)/(197)" mol"=(1)/(197)xx6.02xx10^(23)" ATOMS"` (ii) `"1 g Na"=(1)/(23)" mol"=(1)/(23)xx6.023xx10^(23)" atoms"` (iii) `"1 g Li "=(1)/(7)" mol"=(1)/(7)xx6.02xx10^(23)" atoms"` (IV) `"1 g Cl"_(2)=(1)/(71)" mol"=(1)/(71)xx6.02xx10^(23)" MOLECULES"=(2)/(971)xx6.02xx10^(23)" atoms."` Thus, 1 g of Li has the largest number of atoms. |
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| 565. |
Which homologous series do the hydrocarbons with general formula C_n , H_(2n) belong to? [alkane, alkene, alkyne] |
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Answer» |
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| 566. |
Write the chemical formula of bleaching powder, How is bleaching powder prepared ? For what purpose it is used in drinking water ? |
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Answer» Solution :The chemical formula of bleaching powder is `CaOCl_(2)`. It is prepared by the ACTION of CHLORINE on dry slaked lime `[Ca(OH)_(2)]` Bleaching powder is USED for disinfecting drinking water to make it free from germs. |
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| 567. |
Which bases are called alkalies ? Give an example for alkali. |
| Answer» Solution :Water SOLUBLE bases are called alkalies. EB : Sodium HYDROXIDE (NAOH). | |
| 568. |
The usefulness of a universal indicator is that |
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Answer» it gives a BETTER result |
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| 569. |
Which one of Na, Mg , Fe , and Cu has greater tendency to form ions? |
| Answer» ANSWER :A | |
| 570. |
Which has the maximum number of moleculesamong the following ? |
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Answer» 44 g of `CO_(2)` |
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| 571. |
Which of the following alloys contains Tin ? |
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Answer» brass |
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| 572. |
The second most abundant metal available next to aluminium is ……………. . |
| Answer» Answer :D | |
| 573. |
What is a mixture ? |
| Answer» SOLUTION :A mixture is a substance FORMED when TWO or more ELEMENTS or COMPOUNDS are mixed together in any proportion . | |
| 574. |
What is called double displacement reaction ? Give examples. |
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Answer» Solution :Chemical REACTION in which two reactants react by EXCHANGE of ions is CALLED double displacement reaction. EXAMPLES: (1) `Na_(2)SO_(4)(aq) +BaCl_(2)(aq) to BaSO_(4)(s)+ 2NaCl(aq)` (2) `2KBr(aq)+ BaI_(2)(aq) to BaBr_(2)(s)+ 2KI(aq)` |
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| 575. |
What happens when silver chloride is exposed to sunlight? Write a chemical equation for this reaction. Also give one use of such a reaction. |
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Answer» Solution :When silver chloride is exposed to light, it decomposes to FORM silver METAL and chlorine gas. `2AgCl(s)OVERSET("Sunlight")rarr2Ag(s)+Cl_(2)(G)` This reaction is used in black and white photography. |
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| 576. |
Write the group and period numbers of sodium from its electronic configuration(Na = 11 = 2, 8, 1) |
| Answer» SOLUTION :From the electronic configuration of sodium (Na = 11 = 2, 8, 1), we FIND that there is one ELECTRON in its outermost shell (third shell). Therefore, sodium is an element of group 1 and period 3. | |
| 578. |
What happens when a magnesium ribbon is ignited ? Give chemical reaction. |
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Answer» SOLUTION :`2Mg+O_(2)to2MgO` MAGNESIUM ribbon burns with a DAZZLING light. |
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| 579. |
To protect tooth decaywe are advised to brush our teeth regularly. The nature of the tooth paste commonly used is |
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Answer» acidic |
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| 580. |
What happens when (give only balanced equations and write the names of the reactants and products ) Water is added to calcium carbide. |
| Answer» SOLUTION : ETHYNE `(C_2H_2)`is FORMED | |
| 581. |
Write the chemical equation for the reaction that occurs when ethyl ethanoate is allowed to react with caustic soda solution. |
| Answer» Solution :`UNDERSET(" ethyle thanoate")(CH_(3)COOC_(2)H_(5)) + underset("Cacustic SODA ")(NAOH) to underset(" sodium ehtanoate ")(CH_(3)COONa) + underset(" ETHANOL")(C_(2)H_(5)OH` | |
| 582. |
Which of the following do not show the properties of the constituents? |
| Answer» Solution :water | |
| 584. |
Write the name of each of the following functional groups : (i) -OH (ii) -underset(O)underset(||)(C )- |
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Answer» |
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| 585. |
Write the name and formula of the next homologue of methanoic acid. What is its common name? |
| Answer» SOLUTION :ETHANOIC ACID = `CH_3COOH`, its common NAME is ACETIC acid | |
| 586. |
Across the period, electron affinity |
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Answer» REMAIN the same |
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| 587. |
Which of the following statement(s) about Modem Periodic Table are incorrect ? (i) The elements in the Modern Periodic Table are arranged on the basis of their decreasing atomic number. (ii) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic masses. (iii) Isotopes are placed in adjoining group(s) in the Periodic Table. (iv) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number. |
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Answer» (i) only. |
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| 588. |
When ammonium chloride is heated with caustic soda, the gas evolved is…….. |
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Answer» |
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| 589. |
What is meant by 'groups' of Periodic Table ? |
| Answer» SOLUTION :VERTICAL COLUMNS in the PERIODIC Table are CALLED groups. | |
| 590. |
Write down the structural formula of a member of the same homologous series having 3 carbon atoms . |
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Answer» |
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| 591. |
Write the balanced chemical equation and identify the type of reaction : Zinc carbonate(s) to Zinc oxide(s) + Carbon dioxide(g) |
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Answer» Solution :`ZnCO_(3)(s) OVERSET(Delta)to ANO(s)+ CO_(2)(g)` Given REACTION is a thermal DECOMPOSITION reaction. |
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| 592. |
What is observed when fused lead bromide is electrolysed using platinum electrodes ? |
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Answer» A SILVER grey deposit at ANODE , and a REDDISH brown deposit at CATHODE . |
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| 593. |
Which of the following does not belong to the same homologous series? |
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Answer» `CH_(4)` |
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| 594. |
What is aqueous and non-aqueous solution? Give an example. |
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Answer» Solution :Aqueous solution: The solution in which water ACT as a solvent is called aqueous solution. In general, ionic compounds are soluble in water and FORM aqueous solutions more readily than covalent compounds. E.g. COMMON salt in water. Non - Aqueous solution: The solution in which any liquid, other than water act as a solvent is called non-aqueous solution. Alcohols, benzene, ethers, etc., are used as non-aqueous solvents. E.g. SULPHUR dissolved in carbon DISULPHIDE. |
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| 595. |
What is artificial transmutation ? |
| Answer» Solution :Atoms of one ELEMENT can be transmuted into atoms of other elements. In other words, atom is no longer indestructible. It is known as ARTIFICIAL TRANSMUTATION. | |
| 596. |
Write word equations and then balanced equations for the reaction taking place when - |
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Answer» dilute sulphuric acid reacts with zinc granules. (b) Dilute hydrochloric acid reacts with magnesium ribbon Hydrochloric acid + Magnesium `rarr` Magnesium chloride + Hydrogen `2HCl + Mg rarr MgCL_(2) + H_(2)` (c ) Dilute sulphuric acid reacts with aluminium powder Sulphuric acid + Aluminium `rarr` Aluminium sulphate + Hydrogen `3H_(2)SO_(4) + 2Al rarr Al_(2)(SO_(4))_(3) + 3H_(2)` (d) Dilute hydrochloric acid reacts with iron filings. Hydrochloric acid + `Fe rarr` Iron chloride + Hydrogen `6HCl + 2FE rarr 2FeCl_(2) + 3H_(2)` |
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| 597. |
What are amphoteric oxides ? Give examples. |
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Answer» Solution :Those OXIDES that behave as both acidic and BASIC oxides are callled AMPHOTERIC. EX: Aluminium oxide `(Hl_(2)O_(3))` Zinc oxide `(ZnO)` |
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| 598. |
What is meant by metallurgy ? |
| Answer» SOLUTION :The extraction of METALS from their ORES and then refining them for USE is known as METALLURGY. | |
| 599. |
What were the limitations of Dobereiner's classification? |
| Answer» Solution :Dobereiner.s SYSTEM of classification was FAILED to arrange all the elements in the FORM of triadshaving similar chemical properties. Dobereiner could identify only THREE triads from the elements known at that time. | |
| 600. |
Which element has a total of three shells, with four electrons in its valence shell? |
| Answer» SOLUTION :SI (2,8, 4) | |
