10ml mixture containing 0.1M $NaHC{O}_3$  and 0.1M $N{a}_{2}C{O}_3$  is titrated against an acid with an acid-base indicator. Among the following which observations is/are correct

When phenolphthalein indicator used, end point observed when 10ml of 1M HCl is added

After getting end point with phenolphthalein if we add methyl orange indicator, to get next end point 20ml of 0.1M HCl is to be added furtherly

When methyl orange indicator used from the beginning, end point observed when 6ml of 0.5M HCl added

When phenolphthalein indicator is used, gram equivalent weight of  $N{a}_{2}C{O}_3$ is 106g but when methyl orange indicator used gram equivalent weight of $N{a}_{2}C{O}_3$ is 53g