Question

1) some substances expierence a chemical rxn when mixed. What is the evidence from your observations that a chemical rxn took place?

2) Some substances have acidic or basic properties. What is the evidence for this?

3) What do all acids have in common?

4) why is HCl a stronger acid than Hc2H3O2? use evidence

Answer 1

1 Formation of precipitate, change in color, emission of light , emission of gas, or change in temperature. If any of these changes occur than it can be said that the chemical reaction took place.

2. Acids are chemical compounds that when mixed in water it has a sharp taste, a corrosive action on metals, and the ability to turn certain blue vegetable dyes red whereas the Bases are chemical compounds that in solution are soapy to the touch and turn red vegetable dyes blue. When bases are mixed with acids it neutralize one another and produce salts, which are substances with a salty taste and has none of the characteristic properties of either acids or bases.

3. All acids give rise to hydrogen ions in aqueous solution. All acids dissociate in solution and give hydrogen ions.

4. HCl dissociates completely in water and gives more H+ ions whereas HC2H3O2 dissociated partially in water giving less H+ ions. Due to this HCl is stronger acid than HC2H3O2. It can be observed with the help of the difference in the Ka values

For acetic acid Ka value=> Ka=1.73×10^−5.

For HCl. => Ka=1.3×10⁶.

Thus there is a huge difference .