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.
| 1152. |
On increasing the …….and decreasing the ……….the gas gets converted into liquid. |
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| 1153. |
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide. (a) Is this a physical or chemical change? (b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved. |
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Answer» Solution :(a) It is CHEMICAL change. The chemical equation for the reaction is : calcium carbonate `overset("heat")rarr` Calcium oxide + CARBON dioxide (b) By adding water to calcium oxide taken in a test tube, a basic solution results. It contains calcium hydroxide Calcium oxide + Water `rarr` Calcium hydroxide By passing carbon dioxide through water taken in a tube, CARBONIC ACID is formed. The solution is of acidic nature Carbon dioxide + Water `rarr` Carbonic acid Notes : All the three chemical equations are word equations. Symbol equations can also be written for these. For example, `CaCO_(3) overset("heat")rarr CaO + CO_(2)` `CaO + H_(2)O rarrCa(OH)_(2)` (basic solution) `CO_(2) + H_(2)O rarr H_(2)CO_(3)` (acidic solution) However, you will learn about these in the next class. |
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| 1154. |
On dissolving chalk powder in water, a suspension is obtained. Give any two reasons to support the fact that the mixture so obtained is a suspension only. |
| Answer» Solution :REASONS : (1) The particles of chalk (a suspension) can be seen by an unaided eye. (2) The particles of chalk (SOLUTE) SETTLE down if the solution is kept UNDISTURBED. | |
| 1155. |
On converting the magnitudes of temperature 308 K, 329 Kand 391 K into Celsius scale, the magnitudes obtaind are respectively as |
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Answer» `33^(@)C, 56^(@)C, 118^(@)C` |
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| 1156. |
On converting 25^(@)C, 38^(@) and 66^(@) to kelvin scale, the correct sequence of temperature will be |
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Answer» 298 K, 311 K and 339 K |
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| 1157. |
On converting 308 K, 329 K and 391 K to Celsius scale, the correct sequence of temperature will be : |
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Answer» `33^(@)C, 56^(@)C` and `118^(@)C` |
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| 1158. |
On converting 25^(@)C, 38^(@)C and 66^(@) to kelvin scale, the correct sequence of temperature will be |
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Answer» 298 K , 311 K and 339 K |
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| 1160. |
Of what is fog and cloud an example ? |
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Answer» Aerosol |
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| 1161. |
Of what is a shaving cream a colloid ? |
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Answer» GAS in liquid |
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| 1162. |
Observe figure the electronic configuration of the second period elements of the group from 13-18 given below. Analyse table 3.1 and find whether there is any relation between the number of shells in an atom and the number of periods? |
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| 1163. |
Observe the apparatus shown and answer the following questions.(a) Identify the apparatus (b) Design an activity to use this apparatus to separate the mixture oil and water. (c ) Write the principle involved in this process. |
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Answer» Solution :(a) The APPARATUS is known as a separating funnel. (b) Two immiscible liquids can be separated if in CASE they differ in their densities. A separating funnel can be used to separate the components of an immiscible LIQUID mixture. 
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| 1164. |
Number of valence electrons in ion are |
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Answer» 16 |
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| 1165. |
Number of valence electrons in carbon is ........... |
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Answer» 2 |
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| 1166. |
Number of neutrons present in Hydrogen atom |
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Answer» 0 |
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| 1167. |
Number of free electron(s) in each carbon of graphite is ______ . |
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Answer» ONE |
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| 1169. |
Now sicentists are talking of five stats of matter. They are solid, liquid, gas plasma and ………..(Bose Kelvin condensation, Bose Newton Condensate, Bose Eistein Condensate) |
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| 1171. |
Non-metals react with oxygen to form ________or ______________oxides. |
| Answer» SOLUTION :N/A | |
| 1172. |
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non malleable and are coloured. (a) Name a lustrous non-metal. (b) Name a non-metal which exists as a liquid at room temperature. (c) The allotrpic form of a non-metal is a good conductor of electricity . (d) Name a non-metal which is known to form the largest number of compounds. (e) Name a non-metal other than carbon which shows allotropy. (f) Name a non-metal which is required for combustion. |
| Answer» Solution :(a) GRAPHITE (CARBON) (B) Bromine (c ) Graphite (Carbon) (d) Carbon (E) SILICON (f) Coke (Carbon). | |
| 1175. |
Na^(+) has completely filled K and L shells explain ? |
| Answer» Solution :The ATOMIC number of Sodium is 11, so neutral sodium ATOM hass 11 electrons and its electronic configuration is 2,8,1. But Na+ has 10 electrons out of 10. K- SHELL CONTAINS 2 and L- Shell, 8 electrons respectively. Thus `Na^(+)` has COMPLETELY filled K and L shells. | |
| 1177. |
Niki, Nita and Nitu study in the 9th standard. They were carrying out three different reversible reactions. When the reaction attained their state of equilibrium, they measured the concentration of each gas present in the equilibrium mixture and calculated the K_(c ) value of each reaction. They were provided with the energy profile diagrams of each reaction. From this information, they prepared the following table. From the data given in the table, calculate which reaction will take the maximum time to reach equilibrium and which one will give the maximum yield. |
| Answer» Solution :More the `E_(a)` value, more is the time TAKEN for the completion of a reaction. HENCE, reaction 2 takes more time for completion. More the `K_(C )` value more is the yield of the PRODUCTS. The yield from reaction 3 is the maximum. | |
| 1178. |
Newlands' periodic table is based on atomic masses of elements and modern periodic table is based on atomic number of elements |
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| 1179. |
Naveen is a student of class IX in a city school. His uncle Ram Dev who lives in a village is not keeping good health. He has a tumour in his body. Ram Dev has come to city alongwith his son Ramesh for treatment. Naveen accompanied them to the most famous hospital for medical check-up and treatment. Whan Ram Dev told the person at the reception desk that he had a tumour, he was asked to go to the oncology department of the hospital. The special doctor (called oncologist) examined the tumour of Ram Dev carefully. He then removed some tissue from the tumour and sent it for biopsy, so as to find whether the tumour was malignant or not. The result of biopsy showed that the tumour was malignant. Thedoctor told Ram Dev that he had come to the hospital at the right time due to which his disease had been detected at an early stage and can be cured successfully. The doctor then recommended radiotherapy forRam Dev. Naveen had come to know of the term ratiotherapy, Naveen could make out what disease isotopes in his class. So, as soon as doctor talked of radiotherapy, Naveen could make out what disease his uncle was suffering from. He also shared his knowledge of this disease with his uncle and his son. (a) What do you think is the disease Ram Dev is suffering from ? Define this disease (b) What are (i) tumour (ii) oncoloy (iii) oncologist, and (iv) biopsy ? (c) What is meant by saying that the tumour is malignant ? (d) What is ratiotherapy ? Explain it working briefly (e) Which ratioactive isotope is usually used in the treatment of this disease by radiotherapy ? How does it work ? (f) What values ae displayed by Naveen in this episode ? |
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Answer» Solution :(a) (i) Ram Dev is suffering from the disease called cancer (ii) Cancer is a disease caused by an uncontrolled division of abnormal cells in a part of the body. (b) (i) Tumour is a swelling of a part of the body caused by an abnormal growth of TISSUE. A tumour does not necessarily mean a cancer (ii) Oncology is the branch of medicine which studies and treats tumours and cancer (iii) An ONCOLOGIST is a doctor who specialises in treating people with cancer (iv) Biopsy is the EXAMINATION of tissues removed from any part of the body of a patient to know that PRESENCE, CAUSE or exent of a disease (such as cancer). (c) By saying that the tumour is malignant, it means that the tumour is cancerous. If a tumour is not cancerous, it is said to be benign (d) Radiotheraphy is the treatment of cancer disease by using high energy radiations such as X-rays, gamma rays and electron beams, etc. In radiotheraphy, the high energy radiations destroy the cancer cells in the affected area of the body and stop them from growing and multiplying. (e) Cobalt-60 radioactive isotope is used in the treament of cancer by radiotheraphy. Cobalt-60 radioisotope emits high energy gamma rays. When thehigh energy gamma radiations are directed very carefully at the cancerous tumour in the human body, the cancerous cells get burnt. (f) The various values displayed by Naveen in this episode are (i) Awareness of cancer disease (ii) Knowledge of the treatment of cancer by radiotherapy (by using radioactive isotopes), and (iii) Helping nature. |
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| 1180. |
Natural chlorine consists of two isotopes : 75% ""_(17)^(35)Cl and 25% ""_(17)^(37)Cl. Calculate the average atomic mass of chlorine . |
| Answer» SOLUTION :AVERAGE ATOMIC MASS `=(35xx75+37xx225)/(100)=35.5` | |
| 1181. |
Name various food additives and explain their functions. |
Answer» SOLUTION :
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| 1182. |
Name two substances that show sublimation. |
| Answer» Solution :Ammonium CHLORIDE and NAPHTHALENE (ALSO CAMPHOR). | |
| 1183. |
Name two metallic elements having different valencies. |
Answer» SOLUTION :
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| 1184. |
Name two diatomic non-metallic elements. |
| Answer» SOLUTION :OXYGEN and CHLORINE are DIATOMIC non-metallic ELEMENTS. | |
| 1185. |
Name the two phases in separation of the mixtures in chromatography. |
| Answer» SOLUTION :(a) MOBILE PHASE (B) STATIONARY phase | |
| 1186. |
Name the three subatomic particles of ab atom. |
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Answer» Solution :The THREE subatomic particles of an atom are: (1) electron (NEGATIVELY charged), (2) PROTON (positively charged ] and (3) neutron (no charge ). [electron `""_(o)e^(-1)`. Proton `""_(1)p^(+1)` : neutron `""_(n)n^(@)`] |
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| 1187. |
What are the three subatomic particles ? (AS_(1)) |
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Answer» Solution :The three SUB - atomic PARTICLES of an ATOM are : (a) PROTONS (B) Electron and (c ) Neutrons |
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| 1188. |
Name the three safer resin codes of plastics and describe their features. |
Answer» SOLUTION :
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| 1189. |
Name the three sub-atomic particles of an atom. |
| Answer» SOLUTION :The SUB atomic aprticles in an ATOM are :n protons , electrons and NEUTRONS | |
| 1190. |
Name the term used to denote the conversion of vapour into solid . |
| Answer» SOLUTION :SUBLIMATION | |
| 1191. |
Name the Technique to Separate salt from Sea water |
| Answer» SOLUTION :EVAPORATION | |
| 1192. |
Name the technique to separate : (i) Centrifugation (ii) Evaporation (iii) Sublimation |
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Answer» Solution :(i) CENTRIFUGATION (ii) EVAPORATION (III) SUBLIMATION |
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| 1193. |
Name the technique to separate (i) butter from curd (ii) salt from sea water (iii) camphor from salt. |
| Answer» Solution :(i) CENTRIFUGATION, (II) Evaporation and (iii) SUBLIMATION. | |
| 1194. |
Name the Technique to Separate Camphor from salt |
| Answer» SOLUTION :SUBLIMATION | |
| 1195. |
Name the Technique to SeparateButter and Curd |
| Answer» SOLUTION :CENTRIFUGATION | |
| 1196. |
Name the scientist who proposedthe concept of the distribution of electrons in discreteenergy levels. |
| Answer» SOLUTION :NIELS BOHR | |
| 1197. |
Name the property which is shown by ammonium chloride but not by shodium chloride . |
| Answer» SOLUTION :SUBLIMATION | |
| 1198. |
Name the properties that decide wheather a given substances exists as a solid, liquid or gas |
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Answer» Solution :The PROPERTIES are :- * SPACE between MOLECULES * Force of attraction between molecules * The KINETIC energy of the molecules |
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| 1199. |
Name the process the occurs when a pallet of comphor left exposed to air slowly disappears . |
| Answer» SOLUTION :SUBLIMATION | |