An alloy of chromel containing ni, fe & cr was analysed by a complexometric titration using edta as the titrant. the solution of the alloy was prepared by dissolving 0.7176g of alloy in hno3 and then diluted to mark in 250cm³ volumetric flask. 50cm³ of this aliquot of the sample was treated with pyrophosphate to mark the iron and chromium. if this aliquot of the sample require 26.14cm³ of 0.058m edta to reach the end point with murexide as the indicator. in a second titration 50cm³ aliquot treated with hexamethylenetetraamine to mask chromium require 35.43cm³ of 0.058m edta to reach the end point. finally, a third 50cm³ of aliquot was treated 50cm³ of 0.058m edta and back titrated with 6.21cm³ of 0.063m cu²+ yo reach the end point with murexide indicator. calculate the percentage of nickel, iron and chromium in the alloy

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

14,16 18 reacts with group

i think that the answer is c

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.