The oxide that gives hydrogen peroxide on treatment with a dilute acid is

Write down the balanced equations for the reaction when:
Calcium phosphate is heated with a mixture of sand and carbon;

If three complex numbers are in A.P. then they lie on a circle in the complex plane.

If $$a,\,b,\,c$$ and $$u,\,v,\,w$$ are complex numbers representing the vertics of two triangles such that $$c = \left( {1 - r} \right)a + rb$$ and $$w = \left( {1 - r} \right)u + rv,$$ where $$w = \left( {1 - r} \right)u + rv,$$ is a complex number, then the two triangles