A student is preparing for the titration of 20.0 mL of an approximately 0.3 M solution of NH3 using HCl . She has a 50.0 mL buret and four possible HCl solutions to fill it with. Which solution would be best for use in her titration?a. 6.00 M HCI(aq) b. 0.3 M HCI(aq) c. 0.200 M HCI(aq) d. 0.100 M HCl(aq)

c. 0.200 M HCI(aq)

Explanation:

The titration of a base as NH3 with hydrochloric acid is:

NH3 + HCl → NH4Cl

Where 1 mole of NH3 reacts per mole of HCl

The recommended volume to read in a burette is between 60 and 80% of its capacity.

That is 60% 50.0mL = 30mL and 80% 50.0mL = 40mL must be spent.

A 6.00M HCl spend:

20mL * (0.3mol/L) * (1L/ 6.00M) = 1mL. This solution is not the ideal for the titration.

A 0.3M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.3M) = 20mL. This solution is not the ideal for the titration.

A 0.200M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.200M) = 30mL. This solution ideal for the titration.

A 0.100M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.100M) = 60mL. This solution is not the ideal for the titration.

Right option is:

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.