Answer:
A. Wipe down the glassware to remove any cleaning solvent.
Explanation:
· Remove stoppers and stopcocks when they are not in use. Otherwise, they may "freeze" in place. You can de-grease ground glass joints by wiping them with a lint-free towel soaked with ether or acetone. Wear gloves and avoid breathing the fumes. The deionized water rinse should form a smooth sheet when poured through clean glassware.
Assuming this is a true or false question, the answer would be True
To make a first step you have to know the balanced form for neutralization formula:

According to this, you can <span>calculate what you are being asked :</span>

Then we have :

Hope everything is clear, here is the exact answer you need :
Answer:
sodium sulphide.
Explanation:
First, let us obtain the percentage of sulphur in both compounds. This is illustrated below:
For sodium sulphide(Na₂S):
Molar Mass of Na₂S = (23x2) + 32 = 46 + 32 = 78g/mol
Percentage of sulphur in Na₂S is given by:
32/78 x 100 = 41%
For zinc sulphide(ZnS):
Molar Mass of ZnS = 65.4 + 32 = 97.4g/mol
Percentage of sulphur in ZnS is given by:
32/97.4 x 100 = 33%
From the results obtained sulphur has the highest percentage by mass in sodium sulphide.