Physics, Chemistry, Mathematics Forums

Why is colour of KMnO4 pink
Mn oxidation no. is 0 then how it is possible?

what happens in the titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator?????????
can i have the equation?????

two rough identical discs are rotatating in the same sense say clockwise with the same angular velocity and are brought in contact with each other
see image........
now the system is having an angular momentum 2Iw into plane............
and on this system there is no external force......so the angluar momentum of this system is constant.....but when both are brought in contact the oppose their rotation and by symmetry both will stop rotating because of the frictional torque which opposes their rotation.......
hence angular momentum of the system is destroyed without the impact of external angular impulse.
please explain.....how the law of conservation of angular momentum is broaken
note:discs are rotatating in the same sense say clockwise.

1)What normal to the curve y+x^2 forms the shortest chord?
2)Tangent at a point P1 (other than (0,0) on the curve y=x^3 meet the curve again at P2 . The tangent at P2 meets the curve at P3 and so on..Show that the abscissae of P1, P2, ......Pn form a G.P.Also find the ratio [area(P1 P2 P3]/[Area P2 P3 P4]?

Answers:
1)root2 x - 2y +2=0
2)1/16

Q:which one of the following an ammeter or a  milliammeter has a higher resistance and why???

Q.1.If the median of a triangle ABC through A is perpendicular to AB then prove that tan A+2tan B=0.

hello friends!!!!!!!!!!!!
i am a new user......
this is really an interesting site.
help me in completing these equations


[Cro4]^-2 + H^+ ------->

[Mno4]^- + [No2]^- + H^+ ----------->

[No3]^- + H2So4 + Fe^2 ---------->

A rectangular hyperbola passes through two fixed points and its assymptotes are in given directions.prove that its vertices lie on an ellipse and hyperbola which intersect orthogonally

Find the locus of intersection of 2 circles(equal) which are described on 2 sides EF and EG of a triangles as chords in a rectangular hyperbola whose centre is middle point of FG and which passes through E,F,G

Q1.which bond angle would result in the maximum dipole moment for the triatomic molecule XY2

1.90 2.120 3.150 4.180