Question

Which sample is basic – the one to which HCl was added or the one to which NaOH was added? Which sample is acidic? How did you verify this?
b. Does the highest value of pH correspond to the most acidic solution or to the most basic solution? What about the lowest pH value? As the pH decreases, is the solution getting more acidic or less acidic? What’s the evidence to support you conclusion?
c. What color indicates that the solution is acidic? What color indicates that the solution is basic? What color indicates a more neutral solution?
d. If you started with a basic solution and acidified it, what color change would you expect to observe? Be specific – for example say the color changes from pink to blue as the solution becomes acidic.

Answer 1

a.NaoH is basic add Methyl orange indicator changes into yellow so NaoH is basic

Hcl is acid Add methyl orange indicator changes ito red colur so the solution is acidic.

acid are bases are easily verify by adding indicators

substance	biue litmus	red litmus	methyl orange	phenaphthlene
acid	red	colour less	red	colourless
base	colour less	blue	yellow	pink
neutral	no change	no change	orange	courless

the sample Basic means weak acid and strong base is added the substance is Basicsalts are formed

Hcl is acidic means weak base and strong acid is added . the substance is acidicsalts are formed

ex.HCl add methyl orange indicator it changes into red colour.

NaoH is add methyl orange indicator it changes into yellow colour.ena

Acid + base ------>salt +water

experiment : take test tube pour 10 ml of base and add two or three drops phenaphthlene incator it changes pink colour and few ml of acid is add pink colour disapper this solution is neutralised. to form salt and water.

b, the highest value of PH indicates basic nature

pH decreases acidic nature increases

ex.in stromach acidic nature increases roduces so much pain and irritation.

in stromach acidic nature increases pH value decreses

the pH of stromach is 1to 2

the pH decreases 1.2 acidic nature increases cause pain and irritation.

c.

substance	biue litmus	red litmus	methyl orange	phenaphthlene
acid	red	colour less	red	colourless
base	colour less	blue	yellow	pink
neutral	no change	no change	orange	courless

d. yes colour changes this reaction

example. take a test tube and 10 ml of NaoH pour in it. add few drops of phenaphthlene indicator the solution turn into pink color. in this test tube we add HCl is acid drop by drop the solution slowly pink colour dissapper the solution turn into colour less.

this reaction is called neutralisation reaction.

acid + base--->salt +water

Hcl+NaoH ------>Nacl +H20