Tiêu đề XII Chemistry 2024 (Solved Target Paper) ✅

Solved by Sir Nasim Zulfiqar BOARD OF INTERMEDIATE EDUCATION, KARACHI INTERMEDIATE EXAMINATION, 2024 (ONWARDS) Time: 20 minutes CHEMISTRY PAPER – II Max. Marks: 17 (Science Pre-Engineering & Pre-Medical Groups) SECTION ‘A’ (MULTIPLE CHOICE QUESTIONS) – (M.C.Qs.) (Marks : 17) NOTE: i) This section consists of 17 part questions and all are to be answered. Each question carries one mark. ii) The correct answer bubble must be filled on OMR sheet 1) pasted in answer script. iii) Use only blue / black ball point pen or pointer on OMR sheet. iv) Avoid using pencil / White-o pen on OMR sheet. 1. Choose the correct answer for each from the given options: 1) The oxidation states of the elements of group VA: A) +1 and +3 B) -3 and -5 C) -3, +3 and +5 D) +1, -1 and +3 2) Which of the following s-block element form super oxide when burn in air: A) Li B) Na C) K D) Mg 3) In the equilibrium of dichromate-chromate ion the colour of is: 4)  3  5) The knocking of internal combustion engine can be reduced by the following petroleum process: A) Reforming B) Refining C) Distillation D) Condensation CH (OH )COOH 6) How many optical isomers are possible for | CH (Br)COOH A) 2 B) 3 C) 4 D) 5 7) Which of the following pairs of compounds represent functional group isomerism: 8) 9) The Kinetics of Elimination biomolecular reaction is: A) Zero order B) First order C) Second Order D) Third order 10) Lucas reagent is a mixture of: A) Zn and Hg B) Zn and HCl C) ZnCl2 and HCl D) NaOH and CaO 11) Clemmensen reduction is the conversion of aldehydes and ketones into: A) Alkanes B) Alkenes C) Alkyl halides D) Alcohols 12) Formic acid is naturally found in: A) Valciran root B) Bees sting C) Vinegar D) Butter 13) An example of quaternary structure of protein is: A) Myoglobin B) Hemoglobin C) Albumin D) Globulin 14) Drugs that lower the body temperature to normal are known as: A) Antibiotics B) Antipyretic C) Antiallergic D) Anti histamins 15) An example of thermosetting plastic is: A) Polyethene B) PVC C) Nylon D) Bakelite 16) The region of sphere which extend from 11km to 50km from our Earth’s is known as: A) Troposphere B) Stratosphere C) Mesosphere D) Thermosphere 17) Infra red spectroscopy is a technique use to determine: A) Double and triple bonds B) Mass to charge ratio C) Functional group D) Conjugated system xxxxxxxxxx FROM NEW BOOK A) Orange B) The coordination number of cobalt in Green Na3 Co (C2O4 ) C)  is: Yellow D) Red A) 3 B) 4 C) 6 D) 7 A) 1-butene and 2-butene B) Ethanol and dimethyl ether C) n-butane and iso butane D) Diethyl ketone and methyl propyl ketone Benzene burns with Smokey flame because of its: A) Inflammablity B) High carbon % age C) High resonance energy D) Aromaticity
BOARD OF INTERMEDIATE EDUCATION, KARACHI INTERMEDIATE EXAMINATION, 2024 (ONWARDS) Time: 2 Hours 40 minutes CHEMISTRY PAPER – II (MODEL QUESTION PAPER) Max. Marks: 68 (Science Pre-Engineering & Pre-Medical Groups) SECTION ‘B’ (SHORT-ANSWER QUESTIONS) Marks : 36 Note: Answer any Nine part questions. Select Four part questions from Inorganic – General Chemistry and Five part questions from Organic Chemistry. All questions carry equal marks. INORGANIC – GENERAL CHEMISTRY 2. i) Explain the general group trend and irregularities of ionization energy in the periodic table. regularly from top to bottom. OR Give reasons for any four of the following: * Boiling point of halogens increases down the group in the periodic table Ans. Boiling point of halogens increases down the group to increase in the strength of intermolecular attraction. * Electronegativity decreases regularly from top to bottom in s-block elements Ans. Electronegativity decreases regularly from top to bottom in s-block elements due to increase in number of shells. As the number of shells increases the shared pair of electron moves farther away from the nucleus so that the electrostatic attraction between shared pair and nucleus decreases. * Alkali metals are good conductor of electricity Ans. Alkali metals are good conductors of electricity because their valence electron is loosely bonded so that it can behave like a free electron. * Fluorine is the strongest oxidizing agent Ans. Fluorine has the greatest tendency to accept an electron that’s why it is the strongest oxidizing agent. * Multidentate ligands are known as chelating agents Ans. Multidentate ligands can donate more than one electron pair to central metal atom to form a chelate. That’s why they are known as chelating ligands. ii) Give diagonal relationship on any two of the following pair: * Li and Mg * Be and Al * B and Si FROM NEW BOOK
iii) Why transition elements have the tendency to form alloy? Write the name of three alloys of transition element along with their compositions. iv) Write down the IUPAC names of the following complexes: * [Ag(NH3)2]OH diamminesilver(I)hydroxide * [Fe(CN)6] –4 hexacyanoferrate(II)ion * K3[Cr(C2O4)2Cl2] potassiumdichlorodioxalatochromate(III) * [Pt(en)2(NO2)2]SO4 bisethylenediaminedinitroplatinum(IV)sulphate v) What are Pesticides? Write the name of three types of pesticides along with their specific use. 1. Insecticides
2. Herbicides Herbicides are the chemicals which either destroy or stop growing weeds. 3. Fungicides Fungicides ae chemcial substances employed to eliminate undesired fungi that develop within crops. vi) How was ozone layer formed? Explain the causes of depletion of ozone layer: OZONE FORMATION & OZONE DEPLETION Ozone layer is present in stratosphere. This layer plays a vital role in blocking and absorbing maximum portion of Sun’s harmful radiations. The life on Earth would not be possible without the protection of this layer. Ozone is produced in stratosphere due to photochemical reaction of sun rays and oxygen gas. UV radiations of sunlight breaks O2 into free radicals. The oxygen free radicals are then combined with another oxygen molecule to produce ozone. Human activities can contribute to the depletion of ozone layer through the emission of certain chemicals known as Ozone Depletion Substances (ODS). The most considerable human activity that have been responsible for ozone depletion is the release of gases from cooling devices such as refrigerator and air conditioners. Chlorofluoro Carbons (CFCs) is a highly stable gas used as coolant in refrigeration and also a repellent in aerosol spray. When CFC reaches into stratosphere region, it breaks down into free chlorine and fluorine atoms which then react with ozone in UV light and decompose it into oxygen. The best alternative is Hydro Fluro Carbons (HFCs) which do not have chlorine and do not contribute to ozone depletion. vii) What is proton NMR spectroscopy? On what principle it works. Nuclear Magnetic Resonance (NMR) Spectroscopy The nucleus of certain elements exhibits random spin and behave like a tiny magnet due to their charged nature. When an external magnetic field is applied, the spin of nucleus aligned in two ways. (i) It can align in the same direction of the applied magnetic field and it is said to be low energy spin state. (ii) It can be opposite direction to the applied magnetic field and said to be high energy spin state. When a sample of a compound is placed in a strong magnetic field and subjected to radio frequency radiation, the nuclei with specific spin state absorbs energy and flip into a high energy state, this absorption of energy is detected as signals in the NMR spectrum. The solvent used in NMR spectroscopy is usually D2O or DMSO (Di Methyl SulfOxide) The graph of NMR consists of the following parameters. (i) x-axis represents chemical shift which shows position of proton signals relative to TMS (tetramethylsilane). The values are between 0 – 12 ppm relative to TMS. (ii) y-axis represents absorption which shows the intensity of NMR signals. (iii) Peak represents splitting pattern (singlet, doublet, triplet, quartet) due to neighboring protons. ORGANIC CHEMISTRY viii) How is coal produced under the earth crust? Write the name of four types of coal and mention the %age of carbon content in them.