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.
| 151. |
Exoskeleton is absent in class __________A. PiscesB. AvesC. MammaliaD. Amphibia |
| Answer» Correct Answer - Amphibia | |
| 152. |
In ______ the exoskeleton is absent.A. AmphibiaB. AvesC. ReptiliaD. Mammalia |
| Answer» Correct Answer - Amphibia | |
| 153. |
_______ has the power of regeneration.A. CockroachB. Star fishC. FrogD. Sparrow |
| Answer» Correct Answer - Starfish | |
| 154. |
External Fertilization |
| Answer» If the union of male and female gametes takes place outside the bodies of both organisms, then the fertilization is called as external fertilization. | |
| 155. |
My digits are without claws and external ear is absent. Which class do I belong to? |
| Answer» Correct Answer - Amphibia | |
| 156. |
In _______ the fertilization is external.A. FrogB. BatC. SnakeD. Parrot |
| Answer» Correct Answer - Frog | |
| 157. |
Scorpion, Earthworm, Nereis, Leech |
| Answer» Scorpion - Others belong to Annelida whereas Scorpion belongs to Arthropoda. | |
| 158. |
On keeping iron nails in a blue coloured copper sulphate solution, it is observed that the colour of the solution turns light green after sometime. Give reasons for this colour change. Name the type of reaction. |
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Answer» It is an example of metal displacement reaction. Iron has displaced copper from copper sulphate solution and has changed to iron sulphate which is light green in colour. `Fe(s)+underset("Blue")(CuSO_(4)(aq))rarrunderset("Light green")(FeSO_(4)(aq)+Cu(s))` |
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| 159. |
A student added few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, she added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate. In which test tube or test tubes will she observe colour change ? On the basis of this experiment, state which one is the most reactive metal and why? |
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Answer» The chemical reactions involved in all the four tubes are listed. `"Test tube A : "underset("(Lightgreen)")(3FeSO_(4)(aq))+2Al(s)rarrunderset("(Colourless)")(Al_(2)(SO_(4))_(3)(aq))+3Fe(s)` `"Test tube B : "underset("(Blue)")(3CuSO_(4)(aq))+2Al(s)rarrunderset("(Colourless)")(Al_(2)(SO_(4))_(3)(aq))+3Cu(s)` `"Test tube C : "underset("(Colouless)")(Al_(2)(SO_(4))_(3)(aq))+Fe(s)rarrunderset("(No colour change)")("No chemical reaction")` `"Test tube D : "underset("(Blue)")(Cu(SO_(4))(aq))+Fe(s)rarrunderset("(No colour change)")(FeSO_(4)(s)+Cu(s))` Change of colour will be observed in test tubes A, B, and D while the solution will remain colourless in test tube C. On the basis of the chemical reactions, listed above, Aluminium (Al) is the most reactive metal because it has displaced all other metals from their aqueous salt solutions. |
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| 160. |
Take five test tubes and label them as A, B, C, D and E. Add 5 mL of five unknown solutions in them. Put a small strip of universal indicator in each of them. Following colours appear in these : Solution A-Orange, Solution B-Green, Solution C-Red, Solution D-Blue, Solution E-Violet. Predict the nature of the solutions in these from the pH character. |
| Answer» Solution-A (Weakly acidic), Solution-B (Neutral), Solution-C (Strongly acidic), Solution-D (Weakly basic), Solution-E (Strongly basic). | |
| 161. |
What were the limitations of Döbereiner’s classification? |
| Answer» Doberiener was in a position to identify three triads. It could not apply to all the elements known at that time. Therefore. the classification was not so useful. | |
| 162. |
Use Mendeléev’s Periodic Table to predict the formulae for the oxides of the following elements: K, C, AI, Si, Ba. |
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Answer» K is in group 1. Therefore, the oxide wll be `K_(2)O` C is the group 4. Therefore, the oxide will be `CO_(2)`. Al is in group 4. Therefore, the oxide will be `Al_(2)O_(3)` Si is in group 4. Therefore, the oxide will be `SiO_(2)` Ba is in group 2. Therefore, the oxide will be BaO. |
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| 163. |
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.A. The elements become less metallic in nature.B. The number of valence electrons increases.C. The atoms lose their electrons more easily.D. The oxides become more acidic. |
| Answer» (c ) The atoms lost their electrons more easily | |
| 164. |
Arrange the following in decreasing atomic size : (i) Na, Mg, K (ii) N, F, O (iii) N, S, P |
| Answer» (i) K, Na, Mg (ii) N , O, F (iii) P, S, N. | |
| 165. |
Two elements X and Y belong to group 1 and 2 respectively in the same period. Compare them with respect to: (a) the number of valence electrons (b) valency (c) metallic character (d) size of the atoms (e) formulae of their oxides and chlorides. |
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Answer» (a) The valence electrons present in element X (group 1) and element Y (group 2) are 1 and 2 respectively. (b) The valency of the element X is one while that of the element Y is two. (c) Metallic character decreases along a period. This means that the element X is more metallic as compared to element Y. (d) Atomic size decreases along a period. As a result, the element Y has a smaller size than the element X. (e) For element X : oxide `(X_(2)O),` chloride (XCI). For element Y : oxide (YO) and chloride `(YCl_(2)).` |
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| 166. |
The elements with atomic number 3 to 10 belong to the second period. Taking into account the trends in the general periodic properties, predict. (a) The most electronegative element (b) The most electropositive element (c) The element belonging to noble gas family (d) The element which constitutes large number of organic compounds. (e) The element most abundant in air |
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Answer» (a) The most electronegative element has atomic number (Z) = 9. It is fluorine (F). (b) The most electropositive element has atomic number (Z) = 3. It is lithium (Li) (c) The element belonging co noble gas family has atomic number (Z) = 10. It is neon (Ne) (d) The element which constitutes large number of organic compounds has atomic number (Z) = 6. It is carbon (C). (e) The element most abundant in air is nitrogen (N). It is present as `N_(2).` |
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| 167. |
Two elements M and N belong to group I and II respectively and are in the same period of the periodic table. How do following properties of M and N vary ? (a) Size of their atoms (b) Their metallic character (c) Their valencies in forming oxides (d) Formulae of their chlorides |
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Answer» Element N is placed (group II) after element M (group I) in the same period. This means that (a) Size of atom N is smaller than that of M. (b) Element M is more metallic than element N (c) Valence of element M (group I) = 1 Valency of element N (group II) = 2 (d) Formulae of chlorides : `MCl" and "NCl_(2)` |
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| 168. |
Two elements X and Y belong to group 1 and 2 respectively in the same period of periodic table. Compare these elements with respect to (i) number of electrons in their outermost orbits (ii) their valencies (iii) metallic character (iv) their atomic size (v) formula of their chlorides (vi) formula of their sulphates |
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Answer» (i) The element X and Y have 1 and 2 electrons in their valence or outermost orbits. (ii) The valencies of the element X and Y are 1 and 2 respectively. (iii) The element X is more metallic than element Y. (iv) The atomic size of element X is more than that of Y. (v) The chlorides of the elements are `XCl "and "YCl_(2).` (vi) The sulphates of the elements are `X_(2)SO_(4)" and "YSO_(4).` |
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| 169. |
By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?Ga Ge As Se Be |
| Answer» Since Be lies to the extreme left hand side of the periodic table, Be is the most metallic among the given elements. | |
| 170. |
Name of elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice? |
| Answer» The two elements which will show chemical reactions similar to magnesium are beryllium (Be) and calcium (Ca). This is because beryllium and calcium to the same group of periodic table as magnesium (which is group 2). All of them have similar electronic configurations with 2 valence electrons each. | |
| 171. |
Arrange the following elements in the order of their decreasing metallic charcter Na, Si, Cl, Mg, Al.A. `ClgtSigtAlgtMggtNa`B. `NagtMggtAlgtSigtCl`C. `NagtAlgtMggtClgtSi`D. `AlgtNagtSigtCagtMg.` |
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Answer» Correct Answer - B The metallic character of the elements decreases along a period. These elements are present in third period. |
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| 172. |
The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belongs to the same group ?A. A and BB. B and DC. A and CD. D and E. |
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Answer» Correct Answer - C Elements A (Z = 9) and C (Z = 17) belong to the same group. It is a halogen family (group 17). |
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| 173. |
Devendra was told that the elements `P,Q` and `R` belong to group 2 , group 14 and group 17, respectivelhy, of the long form of periodic table. Based on this information, he was asked to answer the following questions:(a) What is the valency of (i) element `P` (ii) element `Q` and (iii) element `R`? Give reasons for your answer. (b) What is nature of oxide of (i) element `P` (ii) element `Q` and (iii) element `R`? Give reasons for your answer. (c) Give one example each of (i) element `P` (ii) element `Q` and (iii) element `R`. (d) Name three elements which occur in the same group as element `R` but exist in three different physical states at room temperature. (e) What values are displayed by Devendra in answering these question? |
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Answer» (a) (i) The valency of element `P` is 2. This can be explained as follows.The elements of group 2 of periodic table have 2 valence electrons each in their atoms. So, the atom of this element can lose 2 valence electrons (to some other atom), to attain the nearest inert gas electron configuration and hence shows a valency of 2. (ii) The valency of element `Q` is 4. This can be explaine as follows: The elements of group 14 of periodic table have `14-10=14` valence electrons each in theri atoms. An atom of his element can share its 4 valence electrons with 4 more electrons to achieve the nearest inert gas electron configuration and hence shows a valency of 4. (iii) The valencey of element `R` is 1. This can be explained as follows: The elements of group 17 of periodic table have `17-10=7` valence electrons each in their atoms. An atom of this element having 7 valence electrons can accept 1 more electron to complete the stable, inert gas electron configuration and hence shows a valency of 1. (b) (i) The elements of group 2 of periodic table are metals.Now,metals form basic oxides. So, the nature of oxide of element `P` is basic. (ii) The elements of group 14 of periodic table are non-metals. Now, non-metals form acidic oxides. So, the nature of oxide of element `O` is acidic. (iii) The elements of group 17 of periodic table are also non-metals. Now, non-metals form acidic oxides. So, the nature of oxide of element `R` is acidic. (c) (i) An example of element `P` of group 2 is magnesium (`Mg`) (ii) An example of element `Q` of group 14 is carbon `(C)`. (iii) An example of element `R` of group 17 is chlorine `(Cl)`. (d) Element `R` occurs in group 17 of periodic table which compirses halogen elements. So, in group 17 of periodic table: (i) iodine is a solid element. (ii) bromine is liquid element, and (iii) chlorine is a gaseous element. (e) The various values displayed by Devendra in answering these questions are (i) Knowledge of the characteristics of groups of the periodic table, and (ii) Application of knowledge in solving problems. |
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| 174. |
The two isotopes of chlorine have atomic mass 35 u and 37 u. Should they be placed in separate slots in the periodic table ? |
| Answer» No, they should be placed in the same slot (or position) because the periodic table is based on the atomic numbers of the elements. Both the isotopes of the element chlorine have the same atomic number (Z = 17). | |
| 175. |
Arrange the following elements in the order of their increasing non-metallic character Li, O, C, Be, FA. `FltOltCltBeltLi`B. `LiltBeltCltOltF`C. `FltOltCltBeltLi`D. `FltOltBeltCltLi` |
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Answer» Correct Answer - B The non-metallic character of the elements increases along a period. These elements are present in second period in the order Li, Be, C, O, F. |
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| 176. |
Which of the following set of elements is written in order of their increasing metallic character ?A. `Be" "Mg" "Ca`B. `Na" "Li" "K`C. `Mg" "Al" "Si`D. `C" "O" "N` |
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Answer» Correct Answer - A These elements belong to group 2. These are written in increasing order of their size. Since the metallic character increases down the group, the order is the correct. |
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| 177. |
Isotopes of an element have : (a) the same physical properties (b) different chemical properties (c) different number of neutrons (d) different atomic numbersA. (i), (iii) and (iv)B. (ii), (iii) and (iv)C. (ii) and (iii)D. (ii) and (iv). |
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Answer» Correct Answer - D Isotops of an element have same atomic number (ii) and same chemical properties (iv). |
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| 178. |
An element 'X' has mass number 35 and number of neutrons is 18. Identify group number and period of the element 'X'. |
| Answer» Atomic number of X = Mass No. - No. of neutrons = 35 - 17 = 18. Electronic configuration = 2, 8, 7, Group No. = 17, Period No. = 3. | |
| 179. |
Identify the elements from the following characteristics and arrange them in increasing order of metallic character. (a) An element which imparts golden yellow colour to the flame. (b) An element whose oxide is used as a white wash. (c) An element which is constituent of of chlorophyll i.e. green colouring matter in plants. |
| Answer» (a) Sodium (b) Calcium (c) Magnesium. Element sodium (Na) belongs to group 1. Both calcium (Ca) and magnesium (Mg) are present in group 2. The element Ca is placed below Mg in the group. Since the metallic character of the elements decreases along a period and increases down the group, in the light of these observations, the increasing order of metallic character is : `MgltNaltCa.` | |
| 180. |
Identify the elements X a from the following information. (a) X has 17 protons and 18 neutrons (b) Y has 17 protons and 20 neutrons. |
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Answer» Both the elements X and Y are the isotopes of the same element chlorine because they have the same number of protons (17). Remember : Two different element cannot have the same number of protons. Therefore, X and Y are the isotopes of the same element. |
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| 181. |
shows bilaternl symmetry.A. AmoebaB. StarfishC. FishD. Jellyfish |
| Answer» Correct Answer - Fish | |
| 182. |
Body Symmetry. |
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Answer» (i)If body of any animal is cut through an imaginary axis, it may or may not produce two equal halves. Depending upon this property, these are different type of animal bodies. (ii) In some animals, there is no such imaginary axis of the body through which we can get two equal halves. Such a body is called as asymmetrical body e.g. Amoeba, Paramoecium, some sponges. (iii) In some animals, if imaginary cut passes through the central axis but any plane of the body, it gives two equal halves. Such a symmetry is known a radial symmetry e.g. Starfish. (iv) In some animals, there is only one imaginary axis of body through which we can get equal halves. It is known as bilateral symmetry. e.g. Insects, fish, frog, birds, human, etc |
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| 183. |
Radial symmetry is observed in ____A. AmoebaB. OctopusC. StarfishD. Fish |
| Answer» Correct Answer - (c) Starfish | |
| 184. |
You want to study a decomposition reaction by taking ferrous sulphate crystals in a boiling tube. List two steps you would follow while doing the experiment. |
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Answer» (i) Take a test tube and dry it completely. (ii) Take a small amount of the given sample in the test tube. Hold it with a clamp and heat the rube over a burner. Crystals will first become dirty white and then change to brown. |
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| 185. |
When a few drops of phenolphthalein are added to a dilute solution of sodium hydroxide, a pink colour is produced. What will be the colour of the final mixture when excess of HCI is added to it ? (jusify your answer) Or Arrange the metals iron, magnesium, zinc and copper in the increasing order of their reactivity. What will be the two observations made by the student when iron filings are added to copper sulphate solution ? |
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Answer» Phenolphthalein acquires pink colour in sodium hydroxide solution because of its basic nature. On adding excess of HCl, the solution will become acidic and the solution will change colour from pink to colourless. Or The increasing order of the reactivity of metals is : `CultFeltZnltMg.` The displacement reaction taking place in aqueous solution is : `Fe(s)+underset("(Blue)")(CuSO_(4)(aq))rarrunderset("(Light green)")(FeSO_(4)(aq))+underset("(Brown)")(Cu(s))` The observations made from the experiment are : (i) Colour of the solution will change from blue to light green. (ii) Brown deposit will be formed at the bottom of the tube. |
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| 186. |
A ball is thrown vertically upwards with a speed of 120m/s. How much time will it take to reach the ground ? Taking g = 9.8m/s2 and neglecting air resistance. |
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Answer» Given u = 120m/s g = -9.8m/s^2 v = 0 From second equation of motion 0 = 120 - 9.8t 120 = 9.8t t = 12 Total time = 2t = 24s |
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| 187. |
Mendeleev classified elements in order of increasingA. atomic numbersB. chemical reactivityC. atomic massD. valency |
| Answer» Correct Answer - C | |
| 188. |
An element X which is a yellow solid at room temperature shows catenation and allotropy. X forms two oxides which are also formed during the thermal decomposition of ferrous sulphate crystals and are the major air pollutants (a) Identify the element X (b) Write the electronic configuration of X (c) Write the balanced chemical equation for the thermal decomposition of ferrous sulphate crystals ? (d) What would be the nature (acidic/basic) of oxides formed ? (e) Locate the position of the element in the modern table. |
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Answer» (a) The available information suggests that the element X is sulphur. (b) Electronic configuration of S(Z = 16) 2, 8, 6 (c) `2FeSO_(4).7H_(2)O(s)overset("heat")rarrFe_(2)O_(3)(s)+SO_(2)(g)+SO_(3)(g)+7H_(2)O(g)` (d) `Fe_(2)O_(3)" (basic oxide)", SO_(2)" (acidic oxide)", SO_(3)" (acidic oxide)"` (e) Sulphur is a member of group 16 and period 3. |
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| 189. |
Give an account of the process adopted by Mendeleev for the classification of elements. How did he arrive at 'periodic law' ? |
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Answer» The basis of classification of elements adopted was atomic masses of the elements. The elements were arranged in order of increasing atomic masses. Elements with similar properties were kept in a particular grwoup in order of increasing aromic masses. Elements placed in a particular group (or sub group) were having same valency. Note : Please note that when Mendeleev arranged the elements in the Periodic Tabel only 63 elements were known. Even noble gas or inert gas elements were adjust at a later stage. Moreover, many groups were left in the table. |
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| 190. |
Carbon (atomic number 6) and silicon (atomic number 14) are elements in the same group of the periodic table. Give the electronic arrangements of carbon and silicion atoms and state the group in which these elements occur. |
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Answer» Electronic arrangement of carbon : 2,4 Electronic arrangement of silicon : 2, 8,4 Both C and Si belong to group 14. |
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| 191. |
(a) Name metals among first five elements of the Modern Periodic Table. (b) Write their chemical symbols. (c) Write the formula of their oxides. |
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Answer» (a) First five elements in the Modern Periodic Table are : Hydrogen, Helium, Lithium, Beryllium and Boron. Among these, Lithium and Beryllium are metals. (b) The chemical symbols of metallic elements are, Li and Be (c) The formula of the oxides of these elements are : `Li_(2)O" (Lithium oxide) and "BeO` (Beryllium oxide). |
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| 192. |
When water is added gradually to a white solid X, a hissing sound is heard and a lot of heat is produced forming a product Y.A suspension of Y in water is applied to the walls of a house during white washing. A clear solution of Y is also used for testing carbon dioxide gas in the laboratory. (a) What could be solid X? Write its chemical formula. (b) What could be product Y ? Write its chemical formula. (c ) What is the common name of the solution of Y which is used for testing carbon dioxide gas? (d) Write chemical equation of the reaction which takes place on adding water to solid X. (e) Which characteristic of chemical reactions is illustrated by this example ? |
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Answer» (a) The white solid X is quick lime. Its chemical formula is CaO. (b) When water is added to the white solid X, product Y formed is calcium hydroxide. Its chemical formula is `Ca(OH)_(2).` |
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| 193. |
Animals like whale, walrus live in water (ocean). Whether they are included in pisces or mammalia? |
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Answer» (i)Whales and walrus are included in mammalia. They are aquatic mammals. (ii) They are walm blooded animals. (iii) They breath air and mothers feed their babies through mammary glands just like humans do. (iv) Fishes (Pisces) a re cold blooded animals and breathe through their gills and do not have mammary glands. |
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