Question

Could you explain these:

2. Which piece of laboratory equipment should be used to deliver a 10.00 mL sample of acid from a stock container to a flask for a titration? (A) 1.0 mL Beral pipet used 10 times (B) 10 mL graduated cylinder (C) 10 mL volumetric pipet (D) 25 mL beaker

2) C For this one, in general what do you use all the options for? There was another question like this in which the answer was to use a buret, but isn't a buret used only for titrations?

6. 30.0 mL of 0.10 M Ca(NO3)2 and 15.0 mL of 0.20 M Na3PO4 solutions are mixed. After the reaction is complete, which of these ions has the lowest concentration in the final solution? (A) Na+ (B) NO3 – (C) Ca2+ (D) PO4 3–

6) C No clue on this one

46. Which gas-phase atom has no unpaired electrons in its ground state? (A) Li (B) Be (C) B (D) C

46) B but doesn't carbon also have unpaired electrons?

Answer 1

2. The right answer is option c : 10 ml volumetric pipette.

10 ml volumetric pipette will ensure accurate measurement of 10 ml acid solution at once.

Using a 1 ml pipette will require 10 times to transfer the required 10 ml acid solution. This is labour intensive

Hence this option is eliminated.

Using a 25 ml volumetric flask is of no use since we won't be able to measure 10 ml accurately in it.

And using a 10 ml graduated cylinder is also not feasible in this case because filling it to the exact 10 ml mark is difficult. Moreover we are dealing with acid solution which are corrosive for hands and the exposed body parts. Hence these options are eliminated.

Thus using a 10 ml volumetric pipette is safe and accurate.