1, 4, 18, 48, …….. missing number in the series is (1) 100 (2) 78 (3) 92 (4) 112
Answer: (1) 100 Given series: 1, 4, 18, 48, ? To find: Missing terms Solution: To determine the missing numbers... View Article
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Prime factors of the denominator of a rational number with the decimal expansion 44.123 are (1) 2,3 (2) 2,3,5 (3) 2,5 (4) 3,5
Answer: (3) 2, 5 Any number that can be represented in the form of p/q, such that p and q... View Article
Is 41 a prime number?
Answer: A prime number is a positive integer having exactly two factors. If p is a prime, then its only... View Article
Complete the following reaction, P4 + NaOH + H2O →?. Write the balanced equation.
Answer: P4 + 3NaOH + 3H2O → PH3 + 3NaH2PO2. It is a disproportionation reaction, wherein an element is simultaneously... View Article
A mixture of camphor and benzoic acid can be easily separated by a) fractional distillation b) sublimation c) extraction with a solvent d) chemical method
Answer: d) chemical method Explanation: A mixture of camphor and benzoic acid can be easily separated by using an aqueous... View Article
When hydrogen peroxide is added to acidified potassium dichromate, the blue colour produced is due to the formation of: a) Cr2O3 b) CrO5 c) CrO3 d) Cr2O72-
Answer: b) CrO5 Explanation: When acidified potassium dichromate (orange) is oxidized, blue coloured chromium pentaoxide is produced. Here hydrogen peroxide... View Article
Which of the following is ferromagnetic? a) Fe, Co, Ni b) Cu, Ag, Au c) Ca, Sr, Ba d) Zn, Cd, Hg
Answer: a)Fe, Co, Ni Explanation Few substances attract very strongly to the magnetic field, e.g. iron, cobalt, nickel, gadolinium and... View Article
Find out the solubility of Ni(OH)2in 0.1 M NaOH. The ionic product of Ni(OH)2is 2×10-15. a) 1×10-13M b)1×10-8M c) 2×10-13M d)1×108M
Answer: c) 2×10-13 Explanation Ni(OH)2→Ni2++ 2OH– ∴ Ksp= [Ni2+] [OH–]2 ⇒ Ksp= s × (0.1)2 =2×10−15 ⇒ s = 2... View Article
Which of the following are present in a dilute aqueous solution of hydrochloric acid? a) H3O+ + OH– b) H3O+ + Cl– c) unionised HCl d) Cl– + OH+
Answer: b) H3O+ + Cl– Explanation In the aqueous solution, HCl forms hydronium ions and chloride ions. HCl + H2O... View Article
Which of the following is the most stable diazonium salt? a) CH3N2+X– b) C6H5CH2N2+X– c) C6H5N2+X– d) CH3CH2N2+X–
Answer:c) C6H5N2+X– Explanation Diazonium salt where Nitrogen is directly linked to the aryl group is the most stable diazonium salt... View Article
Which of the following elements can be involved in pπ–dπ bonding? a) Nitrogen b) Carbon c) Boron d) Phosphorus
Answer:d) Phosphorus Explanation Phosphorus is present in 3rd period. It contains vacant 3d orbitals, hence, it can be involved in... View Article
CO+H2 is known as a) producer gas b) water gas c) dry ice d) syn gas
Answer: b) water gas Explanation The mixture of CO+H2 is known as water gas or synthesis gas. Producer gas is... View Article
In the reaction, P4 + NaOH + H2O → PH3 + NaH2PO2, the mole ratio of NaH2PO2 and PH3 is :
Answer: 3 Explanation The balanced equation is P4 + 3NaOH + 3H2O → PH3 + 3NaH2PO2, so the mole ratio... View Article
The osmotic pressure of a solution can be increased by : (1) increasing the number of solutes (2) increasing the volume (3) removing semipermeable membrane (4) decreasing the temperature
Answer:(1) increasing the number of solutes Explanation: Osmotic pressure is the minimum pressure that prevents the inward flow of pure... View Article
An LPG cylinder contains 15 kg butane at 27℃ and 10 atm pressure. It is leaking. If its pressure decreases to 8 atm after one day, then the quantity of gas leaked is : (1) 2 kg (2) 1 kg (3) 4 kg (4) 3 kg
Answer: (4) 3 kg Explanation:For an ideal gas PV = nRT Here V1 = V2 R = Ideal gas constant... View Article
The number of atoms in 0.1 mol triatomic gas is: (1) 1.806 × 1023 (2) 6.02 × 1022 (3) 1.8 × 1022 (4) 3.6 × 1023
Answer: (1) 1.806× 1023 Explanation: The number of atoms or molecules in one mole of a substance is represented by... View Article
Under the isothermal condition, a gas at 300 K expands from 0.1 L to 0.25L against a constant external pressure of 2 bar. Find the work done by the gas (given that 1L.bar = 100J) (1) 5kJ (2) -30J (3) 30J (4) 25J
Answer:(2) -30J Explanation: For isothermal expansion of gas: w = −PextΔV = −2 × (0.25−0.1) L.bar = −2 × 0.15 L.bar =... View Article
The empirical formula of a compound is CH2O. Find the molecular formula of the compound if its molecular weight is 180. (1) C5H10O5 (2) C6H12O6 (3) C4H8O4 (4)C3H6O3
Answer: (2) C6H12O6 Explanation: We know that the molar mass of C is 12, O is 16 and H is... View Article
The hybridisation of Ni(CO)4 is: (1) dsp2 (2) sp2 (3) sp3d (4) sp3
Answer: (4) sp3 Explanation: Ni is in zero oxidation state in Ni(CO)4 so the electronic configuration of Ni is 3d8... View Article
14 Dec 2021: UPSC Exam Comprehensive News Analysis
TABLE OF CONTENTS A. GS 1 Related B. GS 2 Related POLITY AND GOVERNANCE 1. Minor cases, major delays INTERNATIONAL... View Article
