141. When an atom absorbs energy the lines in the spectrum will appear which are
A. Brighter
B. Darker
C. Colourless
D. Hard to locate
✅ The correct answer is option B.
Chemistry
Practice the latest Chemistry MCQs with answers and explanations to prepare for exams and job tests. Our collection covers key topics such as atomic structure, periodic table, chemical bonding, organic chemistry, inorganic chemistry, physical chemistry, and environmental chemistry. These Chemistry multiple-choice questions are designed for students, competitive exam aspirants, and professionals appearing in NTS, PPSC, FPSC, CSS, PMS, university entry tests, and medical admission tests. Improve your concepts and problem-solving skills with our updated and comprehensive Chemistry MCQs online.
142. The specific rate constant of a first order reaction depends on the
A. Time
B. The concentration of the reactant
C. Temperature
D. The concentration of the product
✅ The correct answer is option C.
143. When one hydrogen atom of an alkane is removed then it is called
A. Alkene
B. Alkyl
C. Aldehyde
D. Saturated hydrocarbon
✅ The correct answer is option B.
144. Colour of fluorescence produced by cathode rays depends upon
A. Temperature
B. Pressure
C. Volume
D. Composition of glass
✅ The correct answer is option D.
145. On increasing the temperature the rate of reaction increases mainly because
A. The activation energy of the reaction increases
B. The concentration of the reacting molecules increases
C. Collision frequency increases
D. None of these
✅ The correct answer is option C.
146. Alkanes are also known as
A. Saturated hydrocarbon
B. Unsaturated hydrocarbon
C. Paraffins
D. Both A & C
✅ The correct answer is option C.
147. Which one is not true about cathode rays?
A. 9.11×10-31 Kg
B. Cast shadow
C. Heat up the platinum foil
D. Cannot ionize
✅ The correct answer is option D.
148. -d[N2O5]/dt represents
A. The rate of formation of N2O5
B. The rate of decomposition of N2O5
C. Order of the reaction
D. None
✅ The correct answer is option B.
149. Sabatier Senderns reaction involve _________ in presence of Ni
A. Aalkene & H2
B. Alkene & O2
C. Alkene & N2
D. Alkyne & Cl2
✅ The correct answer is option A.
150. Positive rays are produced
A. By burning of gas
B. By cooling of the gas
C. By the bombardment of cathode rays on gas molecules
D. From anode like cathode rays produced from a cathode
✅ The correct answer is option C.