A sample of HCI with an unknown concentration is titrated against 25 mLof 0.5 M NaOH and the following HCI volumes are obtained: 15.2 mL, 15.4mL, 15.8 mL, 15.3 mL. Calculate the concentration of HCI. * 4 \mathrm{NH}_{3}(\mathrm{~g})+7 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 4 \mathrm{NO}_{2}(\mathrm{~g})+6 \mathrm{H}_{2} \mathrm{O}_{(l)} According to the above reaction, what volume of NO₂(g) is produced from the combustion of 100 g of NH3(g), assuming the reaction takes place at standard temperature and pressure? A cylinder of oxygen in a laboratory at 27°C has a pressure of 4atm. The cylinder can withstand an internal pressure of 20 atm. Calculate the temperature at which the cylinder would explode if the building caught fire.