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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.
| 3551. |
Select odd one from the following and justify your answer. Li, Na, Mg, K |
| Answer» SOLUTION :MG is odd ONE because it is an element of group 2, whereas the OTHERS are the elements of group 1. | |
| 3552. |
Select odd one out from the following list of compounds.C_3H_4, C_2H_2, C_2H_6, C_4H_6 |
| Answer» Solution :`C_2H_6` is odd ONE because it is a saturated hydrocarbon, whereas the OTHERS are unsaturated | |
| 3553. |
Select odd one of with justification : (i) NaCl , KCl , NaOH , NH_(4)OH |
| Answer» Solution :`NH_(4)OH` is ODD one because it is WEAK electrolyte , whereas the OTHERS are strong | |
| 3554. |
Select odd one from the following and justify your answer.Li, Be, B, Na |
| Answer» SOLUTION :NA is odd ONE because it is an element of period 3, whereas the others are the elements of period 2. | |
| 3555. |
Select odd one from the following and justify your answer. H, Na, Li, N |
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| 3556. |
Select odd one from the following and justify your answer. F, Cl, Br, O |
| Answer» SOLUTION :O is odd one because it is an element of group 16, WHEREAS the others are the ELEMENTS of group 17. | |
| 3557. |
Select (i) Combination reaction (ii) decomposition reaction and (iii) displacement reaction from the following chemical equations: (i) ZCO_(3)(S) rarrZnO(S)+CO_(2)(g) (ii) Pb(S)+CuCl_(2)(aq)rarrPbCl_(2)(aq)+Cu(s) (iii) NaBr(aq)+AgNO_(3)(aq)rarrAgBr(s)+NaNO_(3)(aq) (iv) H_(2)(g)+Cl(g)rarr2HCl(g) (v) Fe_(2)O_(3)(g)+2AlrarrAl_(2)O_(3)+2Fe(S) (vi) 3H_(2)(g)+N_(2)(g)rarr2NH_(3)(g) |
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Answer» Solution :(i) Decomposition REACTION (II) Displacement reaction (III) Displacement reaction (iv) COMBINATION reaction (v) Displacement reaction (VI) Combination reaction |
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| 3558. |
Select a sweet smelling compound out of the following: |
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Answer» `CH_(3)CH_(2)CH_(2)OH` |
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| 3560. |
Scattering of light by colloidal particles is known as |
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Answer» TYNDALL effect |
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| 3561. |
Say whetherthe following diagrammaticrepresentation in true or false . Give reason. |
Answer» Solution : (i) TRUE . (ii) The size of the ANION is LARGER than the neutral atomand size of the CATION is smaller than the neutral atom. |
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| 3562. |
Saturated hydrocarbons were earlier named as…………………..and by IUPAC system they are named as………………… |
| Answer» SOLUTION :PARAFFINS, ALKANES | |
| 3563. |
Saturated compounds, decolourise the bromine water. |
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Answer» SOLUTION :(i) Unsaturated compounds, decolourise the bromine WATER. (ii) SATURATED compounds do not decolourise the bromine water. |
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| 3564. |
SateaVogadro'sHypothesis . |
| Answer» Solution :AVOGADRO's lawstatesthat" equal volumes of allgas es undersimilarconditionsof TEMPERATUREAND pressurecontainthe equalnumberofmolecules " | |
| 3565. |
Samuel had a silver coin which turned black. He kept the coin in a bowl lined with aluminium foil. Then he filled the bowl with water and boiled it. After sometime, he found that the coin has become new. Its blackness disappeared. How did it happen? |
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Answer» SOLUTION :The blackness of silver COIN is due to the FORMATION of silver sulphide on its surface due to its exposure to air. On boiling, the aluminium foil reacts with the layer of silver sulphide and DISPLACES silver from silver sulphide to FORM aluminium sulphide and silver. This makes the coin shiny. `3Ag_(2)S+2Alrarr6Ag+Al_(2)S_(3)` |
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| 3566. |
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows: Use the table above to answer the following questions about metals A, B,C and D : (1) Which is the most reactive metal?(2) What would you observe if B is added to a solution of copper (II) sulphate ? (3) Arrange the metals A, B, Cand D in the order decreasing reactivity . |
| Answer» Solution :(1) METAL B is the most reactive metal.(2) Blue colour of copper (II) sulphate solution disappears and reddish brown copper metal is deposited on the metal B. (3) Decreasing ORDER of reactivity is B > A > C > D. | |
| 3567. |
Samples of four metals A , B ,C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows: Use the table above to answer the following question about metals A,B ,C and D. (i) Which is the most reactive metal? (ii) What would you observe, if B is added to a solution of copper(II) sulphate? (iii) Arrange the metals A,B,C and D in the order of decreasing reactivity. |
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Answer» SOLUTION :(i) B is most reactive (ii) B will DISPLACE copper from copper (II) SULPHATE (iii) `B gt A gt C gt D` |
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| 3568. |
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows:Use the Table given above to answer the following questions about metals A, B, C and D: (i) Which is the most reactive metal ? (ii) What would you observe if B is added to a solution of Copper(II) sulphate ? (iii) Arrange the metals A, B, C and D in the order of decreasing reactivity. |
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Answer» Solution : (i) Out of iron, copper, ZINC and silver, zinc is at the TOP of activity series. Then comes iron. B givesdisplacement reaction with iron(II) sulphate, therefore, B is most reactive metal. (ii) If B is added to a solution of copper(II) sulphate, displacement reaction will take place. Blue colour of copper sulphate will fade and red-brown PARTICLES of copper will settle down. `B + CuSO_4 to BSO_4 + CU` (iii) The decreasing ORDER of reactivity is : B > A > C > D |
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| 3569. |
Samples of four metals A, B, C and D were taken and were added to the following solutions one by one. The results obtained have been tabulated as follows : {:("Metal",,"Solution to which metal is added",,),(,"Iron(II) sulphate","Copper(II) sulphate","Zince sulphate","Silver nitrate"),("A","No reaction","Displacement","__","__"),("B","Displacement","__","No reaction","__"),("C","No reaction","No reaction","No reaction","Displacement"),("D","No reaction","No reaction","No reaction","No reaction"):}Use the table given above to answer the following questions :(a) Which is the most reactive metal ? (b) What would you observe when B is added to solution of copper(II) sulphate ? (c )Arrange the metals A, B, C and D in order of increasing reactivity. |
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Answer» Solution :Based on the activity series, the relative POSITION of the metals in which involved in solution is : `Zn gt Fe gt Cu gt Ag`. On the basis of the results GIVEN in the table. • Metal A is more reactive than copper and less reactive then IRON. • Metal B is more reactive than iron and less reactive than zinc. •Metal C is only more reactive than silver and less reactive than other metals. •Metal D is equally or less reactive than silver. In the light of above information, we can conclude that (a) Metal B is the most reactive. (b) Since B is more reactive than iron, it is also more reactive than copper. This MEANS that it would displace copper from copper(II) sulphate solution. The blue colour of solution will slowly fade. (c ) The decreasing order of reactivity of metals is :`B gt A gt C gt D`. |
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| 3570. |
Samples of four metals A, B, C and D were taken and added to the following solutions one by one. The results obtained have been tabulated as follows : Use the table given above to answer the following questions about metals A, B, C and D. (i) Which is the most reactive metal ? (ii) Arrange the metals A, B, C and D in the order of decreasing reactivity. |
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Answer» Solution :(i) B (ii) The BLUE colour fades as B displaces CU from `CuSO_(4)` solution (III) `B GT A gt C gt D` |
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| 3571. |
Salts have various uses in everyday life and in _________. |
| Answer» Solution : INDUSTRIES. Salts LIKE baking soda, WASHING soda and plaster of Paris are substances of INDUSTRIAL importance. | |
| 3572. |
Salt formation from acids and alkalis can be stated essentially as the neutralisation of hydrogen and hydroxide ions'. Illustrate it with neutralisation reaction between HCl and NaOH. |
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Answer» Solution :`H^(+)Cl^(-)+NA^(+)OH^(-)toNa^(+)Cl^(-)+H_(2)O` On CANCELLING `Na^(+)andCl^(-)` on the two sides of the neutralisation REACTION, we get `H^(+)+OH^(-)toH_(2)O` |
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| 3573. |
Salt A commonly used in bakery products on heating gets converted into another salt B which itself used for removal of hardness of water and a gas C is evolved. The gas C when passed through lime water, turns it milky . Identify A,B and C. |
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Answer» Solution :Baking powder `(NaHCO_3)` , SALT A is commonly used in bakery PRODUCTS. On heating , if forms sodium carbonate `(Na_(2)CO_(3))` , B and `CO_2` gas, C is evolved . When `CO_2` gas is passed through lime water it form calcium carbonate `(CaCO_3)` , which is SLIGHTLY soluble in water making it milky. `A-NaHNO_(3), ""B-Na_(2)CO_(3), "" C - CO_(2)` gas |
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| 3574. |
Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal of hardness of water and a gas C is evolved. The gas C when passed through lime water, turns it milky. Identify A, B and C. |
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Answer» Solution :Baking powder `(NaHCO_(3))`, salt A is commonly used in BAKERY products. On heating it FORMS sodium carbonate `(Na_(2)CO_(3))`, B and `CO_(2)` GAS, C is EVOLVED. When `CO_(2)` gas is passed through lime water it forms calcium carbonate `(CaCO_(3))`, which is SLIGHTLY soluble in water making it milky. `A - NaHCO_(3) B rarr Na_(2)CO_(3) C - CO_(2)` gas |
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| 3575. |
s-block elements and p-block elements |
Answer» SOLUTION :
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| 3576. |
s' and 'p' block elements except zero group are known as representative elements. |
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Answer» |
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| 3578. |
Rutherford scattering formula fails for very small scattering angles because |
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Answer» the KINETIC energy of ALPHA particles is LARGER |
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| 3579. |
Rusting of iron is a |
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Answer» DISPLACEMENT REACTION |
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| 3580. |
Rusting is an electrochemical process. Justify. If two iron articles are coated with tin and zinc respectively, in which case will the rusting of iron be more rapid, if the coating is worn out in one place. Give a reason. |
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Answer» Solution :Iron when exposed to humid atmosphere gets converted to `Fe^(2+)` due to the formation of `Fe (OH)_(2)` and this is in presence of AIR `(O_(2))` to form rust. `Fe_(2)O_(3). XH_(2)O` When tin COATING on iron is broken iron gets exposed to atmosphere. Since iron has greater oxidation potential than tin, iron acts as anode and tin acts as CATHODE. Iron gets oxidised to `Fe^(+2)` ions in preference to tin. Consequently RUSTING becomes rapid when tin coating on iron is broken. Since Zn has greater oxidation potential than Fe, though Zinc is worn out, Zn present on the rest of the article gets oxidised in preference to Fe. Hence, rusting of Fe is slow. |
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| 3581. |
Rohit's family got a wedding invitation from a relative who lives in a village. Rohitwas very excited. He had never attended a village wedding so he wanted to attend this marriage along with his parents. Rohit's family was invited by the Bride's side. When the marriage party (baraat) reached the village at around 9 PM Rohit noticed that a large number of persons in the marriage party were drunk andsome were still drinking in the cars parked along the roadside. One of the drunk persons (who was a shaprshooter of police in the city) fired two celebratory shots from his licenced gun one of which hit a child sitting on the rooftop andinjured him.After a while some argument started btween two drunk men of the marriage party over a petty matter and they came to blows in full public view. Everyone noticed that bridegroom's uncle was so drunk that he slept thorughtout the marriage ceremonies without eating food at all. While all this drama was unfoldingat marriage venue in the village, a person brought the news that thebridegroom's cousin brother, who was heavily drunk, had met with a car accident and taken to hospital in a serious condition. Being a student of class X Rohit had studied the harmful effects of driking alcohol but today he had seen all this with his own eyes. Rohit's father told him that such things also hapen in many city marriages. Next day, when the intoxication due to alcohol had wornoff, Rohit gathered all the people in marriage andal and gave thema lecture on the harmful effects of drinking alcohol citing horrible incidents of the previous night. Most of the people appreciated Rohit's effort and vowed not to drink alcohol again. (a) Why did a famous sharpshooter fire a gun shot in the wrong direction which hit a child sitting on the rooftop and injured him? (b) Why did a simple argument on a pretty matter between two drunk men lead to a serious quarrel? (c) Why did bridegroom's drunk uncle sleep throughout the marriage ceremonies without eating anything? (d) Why did bridegroom's drunk cousin brother cause a serious car accident? (e) What values are displayed by Rohit in this episode? |
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Answer» Solution :(a) Alcohol drinking slows down the activity of the nervous system and the brain due to which the judgement of a person gets impaired. Because of this impared judgement brought about by drinking alcohol, EVEN a famous sharpshooter fired a GUN shot in the wrong direction injuring a child. (b) Alcohol drinking lowers INHIBITION (mental restrai) due to which drunk men become quarrelsome and come to blows even during simple argument son petty matters. (c) Excessive alcohol drinking causes UNCONSCIOUSNESS. So the bridegroom,s uncle who slept throughout the marriage ceremonies had actually become unconscious. He did not where he was. (d) Alcohol driking increases the reaction time of the driver. A drunk driver cannot press the brake pedal quickly to stop a fast moving car or turn the stearing wheel quickly in an emergency situation to avoid the accident with another running vehicle on the road. This is why brodegroom's drunk cousin brother caused a serious road accident. (e) The values displayed by Rohit are (i) Awareness (or knowledge) of the harmful effects of drinking alcohol, and (ii) Social responsibility (to make VILLAGE people understand the harmful effects of alcohol so as to avoid alcohol). |
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| 3582. |
Rohan was told that sixelements A,B, C,D,E and F have atomic numbers of 2,12,20,18,4 and 10 respectively (where A,B,C,D,E and F are not the chemical symbols of these elements). Based on this information, Rohan was asked to answer the following questions: (a) Which of these elements belong to the same groups of the periodic table? Why? (b) Which of these element belong tothe same periods of the periodic table? Why? (c) Which of these elements are (i) metals, and (ii) non-metals? (d) Which of these elements are chemically (i) reactive and (ii) unreactive? (e) What values are displayed by Rohan in answering the above questions? |
Answer» SOLUTION :First of allRohan wrote down the electronic configurations of all the given six elements as FOLLOWS:  (a) (i) Elements `B(2,8,2),C(2,8,8,2)` and `E(2,2)` belong to the same group (group 2) of the periodic table because all of them have an equal number of 2 valence electrons. (Element A has also 2 valence electronsbut these 2 electrons are in its only electrons shell `K` shell, so it does not belong to group 2). (ii) Elements `A(2),D(2,8,8)` and `F(2,8)` also belong to the same group (group 18) because they are all inert gases having completely filled outermost electron shells WITH8 valence electrons (except element A which has 2valence electrons in its only shell, `K` shell). (b) (i) Element `B(2,8,2)` and element `D(2,8,8)` belong to the same period (3rd period) because they both have 3 electron shells (`K,L` and `K` shells) each. (ii) Element `E(2,2)` and element `F(2,8)` belong to the same period (2nd period) because they both have 2 electron shells (`K` and `L` shells) each. (c) (i) Element B,C and E belonging to group 2 are metals. (ii) Elements A,D and F belonging to group 18 are non-metals. (d) (i) Element B,C and E of group 2 are chemically reactive because they have 2 valence electrons each which they can lose to react with other elements. (ii)Elements A,D and F of group 18 are chemically unreactive because their atoms have completely filled valence shells. They can neither lose electrons nor gain electrons or share electrons to react with other elements. (e) The various values displayed by Rohan in answering these QUESTIONS are (i) Awareness (that in modern periodic classification the elements are arrangedaccording to their electronic configuration (ii) Knowledge (to correlate the properties of elements to their electronic configurations) and (iii) Ability of apply knowledge in solving problems. |
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| 3583. |
Rohan and Vikram are very good friends. Rohan studies in class 9 whreas Vikram studies in class 10. During a dental check up in the school, Rohan was told that tooth decay had just started on the top of his large back teeth and where one tooth touches another. He also heard the dentist telling his assistant that pH change is the cause of tooth decay. Rohan could not understand anything. He told everythig to Vikram. Vikram could understanding what had happened. He explained everything to Rohan and also gave him advice to prevent further tooth deay. (a) What is meant by tooth decay? (b) What type of micro-organisms are responsible for causing tooth decay? (c) How does tooth decay start? (d) What is meant by saying that pH change is the cause of tooth decay? (e) What advice do you thim Vikram gave to Rohan toprevent further tooth decay? (f) What values are displayed by Vikram in this episode? |
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Answer» Solution :(a) Tooth decay is the gradual destruction of the hard, OUTER tissues of the tooth (such as enamel and dentine) leading to the formation of cavities or caries in the tooth. In most SIMPLE terms, tooth decay means rotting of tooth.Progressive tooth decay can LEAD to the death of tooth. (b) Bacteria (which are present in the mouth). (c) When we eat food (including surgary food), some of the food particles stick to our teeth and accumulate on the surface of our teeth. The bacteria present in our mouth brak down the sugar present in these foodparticles to form acid. This acid first attackes the enamel (and then dentine) of our tooth and corrodes it. This starts the tooth decay. (d) The acid formed by the action of bacteria on the surgary food present on out teeth lowers the pH in mouth (making it more acidic). Tooth decay starts when the pH of acid formed in the month falls below 5.5. This is because then the acid becomes strongenough to attack the hard enamel of our teeth and corrode it gradually. This is why it is sid that pH change in the mouth is the cause of tooth decay. (e) Vikram gave the following advice to Rohan to prevent further tooth decay: (i) CLEAN the mouth throughly after eating food by rising with lots of clean water so as to remove the food particles sticking on the surface of teeth. (ii) Clean the teeth by brushing by using a toothpase (at least twice a day). The toothpaste is basic in nature. The baisc toothpaste neutralises the excess acid in the mouth and prevents tooth decay. (iii) Eat less of sugary foods like sweets, toffees, chocolates ice cream and candy, etc. (f) The values displayed by Vikeram are (i) Awareness of the cause of tooth decay (ii) Knowledge that toothpaste is basic in nature which can prevent tooth decay, and (iii) Concern for the DENTAL health of his friend. |
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| 3584. |
Roastingis the process in which the ore is heated in the presence of excess air. |
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Answer» |
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| 3585. |
Rishi went to a palmist to show his palm. The palmist used a special lens for this purpose. (i) State the nature of the lens and reason for its use. (ii) Where should the palmist place/hold the lens so as to have a real and magnified image of an object? (iiii) If the focal length of this lens is 10 cm and the lens is held at a distance of 5 cm from the palm, use lens formula to find the position and size of the image. |
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Answer» Solution :(i) The LENS is a convex lens of small focal length. Its use enables the palmist to see lines on the palm of Rishi in details because the lens forms magnified image. (ii) Palmist should hold the lens at a distance slightly greater than its focal length f (INFACT between f and 2f) so as to have a real and magnified image of the object. (iii) Here f = +10 cm and u = -5CM As PER lens formula `(1)/(v)-(1)/(u)=(1)/(f)`, we have `(1)/(v)=(1)/(f)+(1)/(u)=(1)/(10)+(1)/((-5))=(1-2)/(10)=-(1)/(10) RARR v=-10cm` and `m=(v)/(u)=((-10))/((-5))=+2` Thus, a virtual and erect image is formed at a distance of 10 cm from the lens and image is an enlarged image whose size is two times that of the object (i.e., palm). |
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| 3586. |
Rice requires…….soil |
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Answer» Acidic |
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| 3587. |
Respiration is an ………………. type of reaction. |
| Answer» SOLUTION :EXOTHERMIC | |
| 3588. |
Respiration is an exothermic reaction (process). Why ? |
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Answer» Solution : We need ENERGY for staying alive. We get this energy from the diet (food), we eat. Food is broken down into simple substances during digestion. For example, Rice, potatoes and bread consists of CARBOHYDRATES. These carbohydrates are broken down to form glucose. This glucose combines with oxygen in the cells of our body and PROVIDES energy. This reaction (process) is called respiration. THUS, energy is released during respiration process, it is called an exothermic reaction. `C_(6)H_(12)O_(6) (aq)+6O_(2)(aq) to 6CO_(2)(aq)+6H_(2)O(I)+"Energy"` |
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| 3590. |
__________Requiresslightlyalkalinesoil. |
| Answer» SOLUTION :Citrusfruits | |
| 3592. |
Represent with structure of the functional group of soap and detergent. |
Answer» SOLUTION :In SOAP, the FUNCTIONAL group sodium carboxylate `(-COONa)` is linked with HYDROCARBON `(-R)`.  While in detergent, the functional group sodium sulphonate `(-SO_(3)Na)` is linked with hydrocarbon `(-R)`. 
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| 3593. |
Represent the following chemical changes in the form of chemical equations and balance them. (a) A copper coin is placed in a solution of corrosivesublimate, mercuric chloride. The products obtained are cupric chloride and mercury. (b) A piece of (a) sulphur, (b) charcoal burns vigorously whendropped in molten potassium nitrate, because potassium nitrate decomposesto form potassium nitrite and oxygen, and thisoxygen helps to burn charcoal andsulphur giving out carbon dioxide andsulphur dioxide, respectively. (c )Aqueous ammonium hydroxide solution is made to react with aqueous copper sulphate solution and a bluish white precipitate of cupric hydroxide, and ammonium sulphate are formed. |
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Answer» Solution :(a) The copper displaces the mercury from MERCURIC chloride andforms cupric chloride andmercury. `(Cu+HgCl_(2) to CuCl_(2) + Hg)` (B)` 2 KNO_(3) to 2 KNO_(2) + O_(2)` `S + O_(2) to SO_(2)` `C + O_(2) to CO_(2)` (c ) `2NH_(4)OH + CuSO_(4) to Cu(OH)_(2) + (NH_(4))_(2) SO_(4)` |
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| 3594. |
Represent decomposition of ferrous sulphate with the help of a chemical equation- |
| Answer» SOLUTION :`2FeSO_(4)(s) to Fe_(2)O_(3)(s)+SO_(2)(g)+SO_(3)(g)` | |
| 3595. |
Removal of carbon dioxide is known as dehydrogenation. |
| Answer» SOLUTION :REMOVAL of carbon DIOXIDE is KNOWN as DECARBOXYLATION. | |
| 3597. |
Relative molecular mass of sulphuric acid (H_(2)SO_(4)) is calculated as follows: |
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Answer» Solution :Sulphuric ACID CONTAINS 2 atoms of hydrogen, 1 atom of sulphur and 4 atoms of oxygen. Therefore, Relative molecular mass of sulphuric acid `=(2xx"mass of hydrogen")+(1XX"mass of sulphur")+(4xx"mass of oxygen")` `=(2XX1)+(1xx32)+(4xx16)=98` i.e., ONE molecule of `H_(2)SO_(4)` is 98 times as heavy as `1//12^("th")` of the mass of a carbon `-12`. |
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| 3598. |
Relative molecular mass of water (H_(2)O) is calculated as follows: |
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Answer» Solution :A water molecule is made of 2 ATOMS of hydrogen and ONE atom of OXYGEN. So, the relative molecular mass of water `=(2xx"mass of hydrogen")+(1XX"mass of oxygen")` `=(2xx1)+(1xx16)` `=18` i.e., One molecule of `H_(2)O` is 18 times as heavy as `1//12^("TH")` of the mass of a carbon `-12`. |
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| 3599. |
Relativemolecularmass ofa gas_________. |
| Answer» Solution :`("Massof 1 molecule OFTHE GAS")/("Massof 1 atomof HYDROGEN ")` | |
| 3600. |
Relativemolecularmass =_________. |
| Answer» SOLUTION :`2XX` VAPOURDENSITY | |