"1. An impure sample of benzoic acid (C6H5COOH, 122.12 g/mol) is titrated with 0.8067 MNaOH. A 5.109 g sample requires 36.97 ml of titrant NaOH solution to reach the endpoint.What is the percent by mass of benzoic acid in the sample?Sol:Percent by mass tell the percentage of the each compound in a sample.Balancing the equation of benzoic acid and sodium hydroxide we know that they react in1:1 molar ratio. C6H5COOH + NAOH? C6H5COONa + H2OMol of NAOH in 36.97 mL of 0.8067M solution= 36.97/1000 X 0.8067 =0.029 molThe amount of benzoic acid in the given sample= 0.029 mol( as benzoic acid and NaOH reacts in 1:1 molar ratio)Mass of benzoic acid=0.029 X 122.12 = 3.642 g? ? ? ? ? ? ? h ?? ? ? ? ? ? ? ? Percent mass of benzoic acid in the sample = x 100? ? ? ? ? ? ? h ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?= 3.642/5.109 X100= 71.292. Indicate the possible identity/identities of the unknown element X for each of thefollowing by choosing the correct choices. A) XBr3 Sol: Fluorine, Chlorine, Bromine, Iodine and Astatine are halogens. They are placed in group 17of the period table. They are highly reactive non-metallic elements. They have seven valenceelectrons and try to gain one more electron by forming covalent bonds with hydrogen and othermetals to form meal halides. Transition metals are present in 3-12 group of the periodic table.They have 3 to 12 valence electrons. For example: When Bromine reacts with iron (III) it forms Ferric bromide (FeBr3). Similarly,bromine reacts with chromium (III) to form Chromium bromide (CrBr3)Alkali metals are placed in the group 1 of periodic table. They have only one electron in theirouter shell so the possible formula of metal bromide when it reacts with alkali metals is XBr2X + Br2 ? 2XBrThe Alkali Earth metals are placed in the group 2 of the period table. They have two valenceelectrons. So, the possible compound formed is XBr2X + Br2? XBr2Therefore, in the given question, X is transition metal."