Biology 2015 E.C - 2023 G.C 2014 E.C - 2022 G.C Chemistry 2015 E.C - 2023 G.C Civics and Ethical Education 2015 E.C - 2023 G.C English 2015 E.C - 2023 G.C Geography 2015 E.C - 2023 G.C History 2015 E.C - 2023 G.C Physics 2015 E.C - 2023 G.C Chemistry - Grade 12 -2023 G.C Grade 12 students can now access their exam results by visiting the Educational Assessment and Examination Services (EAES) website. Previous1234567891011121314151617Next 70. Which one of the following methods can be used in the laboratory for the preparation of alkynes? Hydrogenation of alkenes with a metal catalyst. Dehydrohalogenation of adjacent dihalides with sodium hydroxide. Heating of sodium salt of an organic acid with soda lime. Dehydration of alcohols with concentrated sulphuric acid. 71. Which one of the following is TRUE about the electrolysis of a molten hypothetical electrolyte, MX? The overall reaction is redox reaction. Electrons are not transferred from one species to the other. M is produced at the anode. X is produced at the negative electrode. 72. During the extraction of an unknown metal, the metallic ore was fused with NaOH in air and then dissolved in water to obtain the soluble unknown metal containing species. Reduction with carbon is followed after the solution is treated with HCl. Finally the obtained oxide is reduced to its metallic form by aluminum. The most probable unknown metal would be Pb Cr Zn Ca 73. Why tin does NOT react with cold water but calcium reacts with cold water quite readily? Due to the pH of water. Due to its physical state. Due to the formation of a thin oxide layer. Due to its less reactive nature. 74. Why is vulcanization performed in natural rubber? To increase the number of monomer unit in the natural rubber. To decrease the number of monomer unit in the natural rubber. To establish cross-links between polymer chain in the natural rubber. To convert the monomer unit in natural rubber in to polymer. Previous1234567891011121314151617Next We have provided these questions from previous years grade 12 Ethiopian Secondary School Leaving Certificate Examination (ESSLCE) exams with the sole purpose of assisting students in their studies and preparations for upcoming exams. Please be aware that these questions are not indicative of future exam content. Good luck with your studies!